TWI506668B - Plasma processing device and plasma processing method - Google Patents

Description

Plasma processing device and plasma processing method

The present invention relates to a plasma processing apparatus and a plasma processing method for applying plasma treatment to a target object such as a semiconductor wafer.

In the manufacturing process of a semiconductor element, various processes such as etching, ashing, and film formation of a target object (semiconductor wafer) are performed. These treatments use a plasma processing apparatus to apply a plasma treatment to the semiconductor wafer in a processing vessel that can be maintained in a vacuum atmosphere.

In recent years, the development of semiconductor wafers has become larger and the components have been miniaturized, and it is necessary to improve the efficiency of plasma processing (for example, film formation speed) and the uniformity of wafer in-plane processing. Therefore, attention is paid to a method of embedding an electrode in a processing chamber of a plasma processing apparatus on a mounting table on which a semiconductor wafer is placed, and supplying high-frequency electric power to the electrode, and applying a bias voltage to the semiconductor wafer simultaneously. A method of plasma treatment (for example, Patent Document 1).

When the high-frequency electric power is supplied to the electrode of the mounting table, the conductive element that is placed at the ground potential of the plasma generating space with respect to the electrode embedded in the mounting table is formed as a counter electrode. In other words, when the bias high-frequency electric power is supplied to the electrodes in the mounting table, the counter electrode is formed from the mounting table via the plasma toward the counter electrode, and the counter electrode is returned to the bias via the processing container wall or the like. Use the high-frequency current path (RF return circuit) of the ground terminal of the high-frequency power supply. When the high-frequency current path as described above cannot be stably formed, the amplitude of the plasma potential (Vp) generated in the processing container becomes large, and it is difficult to stably perform the plasma treatment. Further, when the amplitude of the plasma potential is excessively large, particularly in the treatment at a low pressure of several tens Pa or less, the surface of the counter electrode formed of aluminum or the like is usually sputtered by the action of plasma and is contaminated. Case. In order to suppress the vibration of the plasma potential, it is necessary to sufficiently ensure the area of the counter electrode. However, in the microwave plasma processing apparatus of the prior art of Patent Document 1, since the microwave penetrating plate is disposed in the upper portion of the processing container, it is necessary to sufficiently ensure the counter electrode unlike the plasma processing device of the parallel plate type or the like. The area will have structural limitations.

For the foregoing reasons, there is proposed a plasma processing apparatus in which a ring-shaped pair of tantalum or aluminum is detachably mounted on the inner side of the processing vessel at a peripheral portion of the microwave penetrating plate in the microwave plasma processing apparatus. The electrode is oriented (for example, Patent Documents 2 and 3). In the conventional techniques such as Patent Documents 2 and 3, the plasma potential (Vp) when the high-frequency electric power is supplied to the mounting table can be stably stabilized by sufficiently ensuring the area of the counter electrode. However, since the counter electrode of Patent Documents 2 and 3 is disposed close to the microwave penetrating plate, the effective area for introducing the microwave is narrowed, so that the microwave introduction itself becomes unstable, and the container may not be processed. The plasma is stably generated inside. Further, in the microwave plasma processing apparatus, since the plasma is generated directly under the microwave penetrating plate, the temperature of the electron near the microwave penetrating plate region is the highest. Therefore, as in the case of Patent Documents 2 and 3, when the counter electrode is brought into close contact with the microwave penetrating plate and protrudes toward the processing space, the tip end of the counter electrode is easily melted by the plasma, and there is a concern that contamination occurs.

Patent Document 1: International Publication WO 2009/123198 A1

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 9-266095

Patent Document 3: Japanese Patent Laid-Open No. Hei 10-214823

In view of the above, an object of the present invention is to provide a plasma processing apparatus for supplying a bias high-frequency electric power to an electrode on a mounting table on which a workpiece is placed, thereby suppressing vibration of a plasma potential and stably Produces plasma and prevents contamination due to sputtering of metal counter electrodes.

The plasma processing apparatus according to the present invention includes a processing container in which an opening is formed in the upper portion, and the object to be processed is processed using plasma; and the mounting table is placed in the processing container to mount the object to be processed; the first electrode Is embedded in the mounting table and applies a bias voltage to the object to be processed; the dielectric plate closes the opening of the processing container to define a plasma generating space, and allows microwave penetration to be introduced into the processing container a planar antenna disposed above the dielectric plate and introducing microwaves generated by the microwave generating device into the processing container via the dielectric plate; the cover assembly is disposed on the upper portion of the processing container And having an abutting support portion protruding toward the plasma generating space on the inner peripheral side thereof to support the outer peripheral portion of the dielectric body plate by the abutting support portion; the annular expansion protruding portion Forming a space from the processing container or the abutting support portion toward the plasma in the processing container, and protruding from the dielectric plate at a distance from each other, and forming a space between the plasma and the first 1 electrode in pairs At least a portion of the second electrode; and a space is formed between the line and below the dielectric plate aspects for the expansion portion protrudes above.

In the plasma processing apparatus of the present invention, it is preferable that the distance between the upper surface of the expanded projection and the lower surface of the dielectric plate is in the range of 10 mm or more and 30 mm or less.

Further, in the plasma processing apparatus of the present invention, it is preferable that the expansion protrusion is provided such that the protruding amount of the tip end does not reach above the end portion of the object to be processed placed on the mounting table.

Moreover, in the plasma processing apparatus of the present invention, it is preferable that a space between the dielectric plate and the expanded projection is provided with a gas introduction port into which a processing gas is introduced.

Further, in the plasma processing apparatus of the present invention, the expansion protrusion may be integrally formed with the lid assembly, or the expansion protrusion may be integrally formed with the processing container. Moreover, the expansion protrusion may be an auxiliary electrode assembly fixed to the cover assembly or an auxiliary electrode assembly fixed to the processing container.

Further, in the plasma processing apparatus of the present invention, it is preferable that the surface of the expanded projection is provided with irregularities.

Further, in the plasma processing apparatus of the present invention, it is preferable that a surface area of the second electrode facing the plasma generating space is 1 or more and 5 or less in comparison with an area of the buried region of the first electrode of the mounting table. Inside.

Further, in the plasma processing apparatus of the present invention, it is preferable that the surface of the expanded projection further includes a protective film. In this case, the protective film is preferably made of tantalum.

Moreover, in the plasma processing apparatus of the present invention, it is preferable to further include an insulating plate along the inner wall of the processing container at a position lower than the mounting surface of the mounting table. In this case, preferably, the insulating sheet is formed to reach a position of the exhaust chamber continuously disposed at a lower portion of the processing container.

The plasma processing method of the present invention uses a plasma processing apparatus to generate a plasma in a processing container and process the object to be processed by the plasma; wherein the plasma processing apparatus is provided with a processing container, An opening is formed in the upper portion, and the object to be processed is processed using plasma; the mounting table is placed in the processing container, and the object to be processed is placed in the processing table; the first electrode is embedded in the mounting table, and a bias voltage is applied thereto. a dielectric body plate that closes an opening of the processing container to divide a plasma generating space, and allows microwave penetration to be introduced into the processing container; the planar antenna is disposed above the dielectric body plate And introducing microwaves generated by the microwave generating device into the processing container through the dielectric plate; the cap assembly is disposed on the upper portion of the processing container and has an annular shape, and has a plasma generated on the inner peripheral side thereof Abutting support portion protruding from the space to support the outer peripheral portion of the dielectric plate by the upper portion of the abutting support portion; the annular expansion protruding portion is directed to the processing from the processing container or the abutting support portion Inside the container a plasma generating space protruding from the dielectric plate at intervals, and constituting at least a part of the second electrode paired with the first electrode via the plasma generating space; and a space formed in the space The upper side of the expansion protrusion is between the upper side of the dielectric plate and the lower side of the dielectric plate. In this case, the treatment pressure may be 40 Pa or less.

The plasma processing apparatus of the present invention is provided with a space from the processing container or the abutting support portion and spaced apart from the dielectric plate to the plasma generating space, and is configured to be separated from the plasma generating space. Since at least a part of the second electrode of the pair of electrodes is annularly expanded and protruded, the area of the second electrode can be sufficiently ensured, and the vibration of the plasma potential (Vp) can be suppressed. Further, by increasing the area of the second electrode, it is possible to suppress the surface of the second electrode from being sputtered by the plasma action, thereby preventing contamination. Further, by ensuring a sufficiently large second electrode area, it is possible to suppress short-circuiting and abnormal discharge in other portions. Furthermore, since the expansion protrusions are spaced apart from the dielectric plate, the microwave power can be introduced into the processing container to form a plasma stably in the processing container without reducing the effective area of the dielectric plate. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]

Fig. 1 is a schematic cross-sectional view showing a schematic configuration of a plasma processing apparatus 100 according to a first embodiment of the plasma processing apparatus of the present invention. Further, Fig. 2A is an enlarged cross-sectional view showing the essential part of Fig. 1. 2B is a perspective view showing the appearance of a cover assembly of a structural component of the plasma processing apparatus 100. Further, Fig. 3A is a plan view showing a planar antenna of the plasma processing apparatus 100 of Fig. 1.

The plasma processing apparatus 100 is configured to use a planar antenna having a plurality of slot-shaped holes, in particular, a RLSA (Radial Line Slot Antenna) to introduce microwaves into the processing container, and to generate the inside of the processing container. High density and low electron temperature microwave excited plasma RLSA microwave plasma processing device. The plasma processing apparatus 100 can be processed by using a plasma having a plasma density of 1 × 10 ¹⁰ to 5 × 10 ¹² /cm ³ and a low electron temperature of 0.7 to 2 eV. Therefore, the plasma processing apparatus 100 can be applied to the manufacturing process of various semiconductor devices, for example, oxidizing a tantalum film to be processed to form a tantalum oxide film (for example, a SiO ₂ film), or nitriding to form a tantalum nitride film (for example, SiN film) and other purposes.

The plasma processing apparatus 100 is configured to be a hermetic type, and includes a substantially cylindrical processing container 1 for accommodating a workpiece (semiconductor wafer W, hereinafter simply referred to as "wafer"). The processing container 1 is grounded and is made of, for example, aluminum or an alloy thereof, or a metal material such as stainless steel. Further, the processing container 1 may not be a single container but divided into a plurality of parts. Further, the upper portion of the processing container 1 is provided with a microwave introducing portion 26 for introducing microwaves into the plasma generating space S. That is, the microwave introduction portion 26 is disposed at the upper end portion of the processing container 1. Further, an exhaust chamber 11 is coupled to a lower portion of the processing container 1. The processing container 1 is formed with a plurality of cooling water flow paths 3a to cool the walls of the processing container 1. Therefore, it is possible to suppress the thermal expansion caused by the heat of the plasma, thereby causing misalignment or plasma damage to the joint portion which is in contact with the microwave introduction portion 26, thereby preventing deterioration of the sealing property or generation of particles.

The mounting table 5 for supporting the wafer W in the processing container 1 is provided in a state of being supported by the cylindrical supporting portion 4 extending upward from the center of the bottom of the exhaust chamber 11. The material constituting the mounting table 5 and the support portion 4 may be, for example, a ceramic material such as quartz, aluminum nitride (AlN) or aluminum oxide (Al ₂ O ₃ ), but it is preferable that the materials have good thermal conductivity. AlN. Further, the mounting table 5 is provided with a resistance heating type heater 5a, and the mounting table 5 is heated by power supply from an AC power source (heater power source 6) of, for example, 200 V, and the heat is used to heat the object to be processed (crystal Round W). A power supply line 6a that connects the heater 5a and the heater power source 6 is provided with a filter box 45 capable of filtering out RF (high frequency). The temperature of the mounting table 5 is measured by a thermocouple not shown in the figure inserted in the mounting table 5, and the heater power source 6 is controlled according to the signal from the thermocouple, and the temperature can be stably controlled to, for example, room temperature to Within the range of 800 °C.

Moreover, the surface side of the inside of the mounting table 5 is embedded with the bias electrode 7 as the first electrode above the heater 5a. This electrode 7 is embedded in a region roughly corresponding to the wafer W placed on the mounting table 5. As the material of the electrode 7, a conductive material such as molybdenum or tungsten can be used. The electrode 7 is formed into a shape such as a mesh shape, a lattice shape, or a spiral shape. Further, a cover 8a covering the entire surface of the mounting table 5 and the entire surface of the side wall is provided. The cover 8a prevents the plasma from acting on the mounting table 5 and causes sputtering to cause metal contamination. In order to guide the wafer W, the surface of the cover 8a is provided with a groove (groove) having a size larger than that of the wafer and having a depth substantially the same as that of the wafer W. The wafer W is disposed at the groove. Moreover, in order to uniformly exhaust the inside of the processing container 1, an annular quartz baffle 8b is provided around the mounting table 5. The spoiler 8b has a plurality of holes 8c supported by posts (not shown). Further, the mounting table 5 is provided with a plurality of wafer support pins (not shown) that can be protruded with respect to the surface of the mounting table 5, and is used to support and lift the wafer W.

The bottom wall 1a of the processing container 1 is formed with a circular opening 10 at a central portion thereof, and the bottom wall 1a is connected to communicate with the opening portion 10 and protrude downward so that the inside of the processing container 1 can be evenly distributed. The exhaust chamber 11 of the ground exhaust. An exhaust port 11b is formed at the side of the exhaust chamber 11, and an exhaust pipe 23 is connected thereto. The exhaust pipe 23 is connected to an exhaust device 24 including a vacuum pump. Then, by the operation of the exhaust device 24, the gas in the processing chamber 1 is uniformly discharged into the space 11a of the exhaust chamber 11, and then exhausted through the exhaust pipe 23. Thereby, the inside of the processing container 1 can be decompressed at a high speed to a specific degree of vacuum (for example, 0.133 Pa). Further, the exhaust pipe 23 may be connected to the bottom surface of the exhaust chamber 11. Further, the exhaust chamber 11 may be formed inside the processing container 1.

Further, the side wall 1b of the processing container 1 is provided with a carry-out port for carrying in and out of the wafer W, and a gate valve for switching the carry-out port (both not shown in the drawings).

The upper portion of the processing container 1 is formed with an opening, and the microwave introducing portion 26 that closes the opening is airtightly disposed. The microwave introduction portion 26 can be turned on/off by an opening mechanism not shown. The main structure of the microwave introduction portion 26 has a cover assembly 27, a microwave penetration plate 28, a planar antenna 31, and a slow wave material 33 in this order from the mounting table 5 side; further, for example, SUS (stainless steel), aluminum, The conductive cover 34 made of a material such as an alloy covers the slow wave material 33. The outer peripheral portion of the cover 34 is fixed to the cover assembly 27 by the fixing member 36 and through the annular retaining ring 35.

The lid assembly 27 has a ground potential and is made of the same material as the processing container 1. In the present embodiment, the annular cover unit 27 is formed with an opening. The inner peripheral portion of the cap assembly 27 is exposed in the plasma generating space S in the processing container 1, and constitutes a counter electrode (second electrode) that faces the lower electrode (electrode 7 of the mounting table 5). The inner peripheral surface of the annular cap assembly 27 is formed with a projection 60 that is more protruded toward the plasma generating space S than the inner wall surface of the processing container 1. As shown in FIGS. 2A and 2B, the protruding portion 60 has an abutting support portion 60A that abuts against the microwave penetrating plate 28 in its upper direction, and is more toward the processing container 1 than the abutting supporting portion 60A. The inner plasma generates an expansion protrusion 60B in which the space S protrudes. Since the abutment support portion 60A and the expansion protrusion portion 60B are formed with a step, when the microwave penetration plate 28 is disposed on the abutment support portion 60A, a loop is formed between the microwave penetration plate 28 and the expansion protrusion portion 60B. Shape space S1. In the present embodiment, the expanded projection 60B mainly functions as a counter electrode. Further, the space S1 constitutes a part of the plasma generation space S.

Further, the lid assembly 27 is provided with a gas introduction port 15a at a plurality of positions (for example, 32 positions) that abut against the inner circumferential surface of the support portion 60A. In other words, between the abutting support portion 60A and the expanded protruding portion 60B, a gas introduction port 15a that is annularly dispersed and opened is formed in the wall of the abutting support portion 60A where the step is formed. Each of the gas introduction ports 15a forms an opening toward the space S1, and the processing gas can be introduced into the space S1, respectively. A gas introduction path 15b extending obliquely is provided from the gas introduction port 15a to the inside of the cap assembly 27, respectively. Further, the gas introduction path 15b may be formed in a horizontal shape. Each of the gas introduction paths 15b communicates with the annular passage 13 formed horizontally on the lid assembly 27 and the upper portion of the processing container 1. Thereby, the processing gas can be uniformly supplied to the plasma generating space S and the space S1 in the processing container 1.

At the abutting portion of the processing container 1 and the lid assembly 27, for example, the sealing members 9a and 9b such as an O-ring are disposed on the outer side and the inner side of the annular passage 13, thereby maintaining the airtight state of the abutting portion. That is, when the microwave introduction portion 26 is closed, the upper end surface of the side wall 1b of the processing container 1 and the lid assembly 27 having the opening function are sealed by the sealing members 9a and 9b. The sealing members 9a and 9b are made of, for example, a fluorine-based rubber material such as Kalrez (trade name; manufactured by DuPont). Further, a plurality of refrigerant passages 27a are formed on the outer peripheral surface of the lid assembly 27. By allowing the refrigerant to flow through the refrigerant passage 27a, the outer peripheral portions of the lid assembly 27 and the microwave penetrating plate 28 can be cooled. Thereby, it is possible to prevent the occurrence of misalignment of the joint portion due to thermal expansion caused by the heat of the plasma, thereby preventing a decrease in sealing property or generation of fine particles.

The microwave penetrating plate 28 as a dielectric plate is made of a dielectric such as quartz or Al ₂ O ₃ , AlN, sapphire, SiN or the like. The microwave penetrating plate 28 has a function of a microwave introduction window, and allows microwaves from the planar antenna 31 to be penetrated and introduced into the plasma generating space S in the processing container 1. The lower surface of the microwave penetrating plate 28 (the side of the mounting table 5) is not limited to a flat shape, and for example, a recess or a groove may be formed in order to homogenize the microwave to stabilize the plasma.

The outer peripheral portion of the microwave penetrating plate 28 is supported by the sealing member 29 in an airtight state on the abutting support portion 60A of the protruding portion 60 of the cap assembly 27. Then, in a state where the microwave introducing portion 26 is closed, the processing container 1 and the microwave penetrating plate 28 divide the plasma generating space S, and the airtightness of the plasma generating space S can be maintained.

The planar antenna 31 has a disk shape, and is engaged with the microwave penetration plate 28 by the outer peripheral portion of the cover 34. The planar antenna 31 is composed of, for example, a copper plate whose surface is plated with gold or silver, a metal plate such as an aluminum plate, a nickel plate, or a brass plate, and has a plurality of slots 32 for radiating electromagnetic waves such as microwaves. The slot 32 is formed through the planar antenna 31, and two pairs of holes are arranged in a specific pattern.

The slot 32 is formed in a long groove shape as shown in FIG. 3A, and the adjacent slots 32 are generally arranged in a "T" shape, and the plurality of slots 32 are arranged concentrically. The length of the slot 32 and the arrangement spacing are determined by the microwave wavelength (λg) in the waveguide 37. For example, the spacing of the slots 32 is configured to be λg/4 to λg. Further, in Fig. 3A, the pitch of adjacent slots 32 formed in a concentric shape is expressed by Δr. Further, the slot 32 may have other shapes such as a circular shape and a circular arc shape. Further, the arrangement of the slots 32 is not particularly limited, and may be arranged in a spiral shape or a radial shape, for example, in addition to concentric circles.

The slow wave material 33 has a larger dielectric constant than vacuum and is disposed on the upper side of the planar antenna 31. For example, the slow wave material 33 is made of a fluorine-based resin such as quartz, ceramic, or polytetrafluoroethylene, or a polyimide resin. Further, since the wavelength of the microwave becomes long in the vacuum, the slow wave material 33 has a function of making the wavelength of the microwave shorter to adjust the plasma. In addition, between the planar antenna 31 and the microwave transmissive plate 28, the slow wave material 33 and the planar antenna 31 may be closely or separately disposed, but preferably in close contact.

The cover 34 is formed with a refrigerant passage 34a through which the cover 34, the slow wave member 33, the planar antenna 31, the microwave penetration plate 28, and the cover assembly 27 are cooled by passing the refrigerant flow therethrough. Thereby, deformation and breakage of these components can be prevented, thereby stably generating plasma. Further, the planar antenna 31 and the cover 34 are in a grounded state.

An opening 34b is formed in the center of the upper portion of the cover 34, and the waveguide 37 is connected to the opening 34b. The end of the waveguide 37 is connected to the microwave generating device 39 via the matching circuit 38. Thereby, the microwave generated at the frequency of the microwave generating device 39, for example, 2.45 GHz, propagates through the waveguide 37 to the planar antenna 31. The frequency of the microwave can also use frequencies such as 8.35 GHz and 1.98 GHz.

The waveguide 37 has a coaxial waveguide 37a having a columnar shape extending upward from the opening 34b of the cover 34, and a transmission mode converter 40 connected to the upper end of the coaxial waveguide 37a in the horizontal direction. An extended rectangular waveguide 37b. The mode converter 40 between the rectangular waveguide 37b and the coaxial waveguide 37a has a function of converting microwaves propagating in the TE mode in the rectangular waveguide 37b into the TEM mode. The inner conductor 41 at the center of the coaxial waveguide 37a extends from the mode converter 40 to the planar antenna 31, and the lower end of the inner conductor 41 is connected and fixed at the center of the planar antenna 31. Further, the planar antenna 31 and the cover 34 form a flat waveguide path. Thereby, the microwave is introduced into the central portion of the planar antenna 31 via the inner conductor 41 of the coaxial waveguide 37a, and is uniformly radiated uniformly and radially therefrom.

Next, the gas supply structure of the plasma processing apparatus 100 will be described. As shown in the enlarged view of FIG. 2A, a plurality of gas supply passages 12 penetrating the inside of the side wall 1b and the bottom wall 1a in the vertical direction are formed at arbitrary portions (for example, four equal portions) of the side wall 1b of the processing container 1. The gas supply passage 12 is connected to the annular passage 13 formed at the upper end portion of the side wall 1b of the processing container 1 and the joint portion of the lower end portion of the cap assembly 27. The annular passage 13 is connected to the gas supply device 16 through the gas supply passage 12 and the gas supply pipe 12a. Further, the gas supply device 16 may be connected to the annular passage 13 from the side surface of the processing container 1 by forming the gas supply passage in the horizontal direction.

The annular passage 13 is a gas passage formed by the step portion 18 and the step portion 19 at the abutting portion of the upper end surface of the processing container 1 and the lower end surface of the cap assembly 27. The step portion 18 is provided on the lower side of the cap assembly 27. The step portion 19 is provided on the upper end surface of the side wall 1b of the processing container 1. This annular passage 13 is formed in a ring shape in a slightly horizontal direction around the plasma generating space S in the processing container 1. Further, the annular passage 13 may be formed by forming a groove (concave portion) at the upper end surface of the side wall 1b of the processing container 1 or the lower portion of the lid assembly 27. The annular passage 13 has a function of uniformly distributing the supply gas to each of the gas introduction paths 15b as a gas distribution mechanism, and is capable of preventing the processing gas from being supplied to the specific gas introduction port 15a and being unevenly supplied into the processing container 1 The function. As described above, in the present embodiment, the processing gas from the gas supply device 16 can be supplied from the gas supply passage 12, the annular passage 13, and the respective gas introduction paths 15b, for example, from the gas inlet ports 15a at 32 positions. The plasma generation space S and the space S1 are uniformly introduced into the processing container 1, so that the plasma uniformity in the processing container 1 can be improved.

Next, a bias voltage applying mechanism that applies a bias voltage to the wafer W placed on the mounting table 5 will be described. The electrode 7 embedded in the mounting table 5 is configured such that a high frequency power source 44 for applying a bias voltage is connected to the power supply line 42 and the matching unit (MB) 43 penetrating through the support portion 4, so that a high frequency can be applied to the wafer W. bias. As described above, the filter box 45 is provided at the power supply line 6a for supplying electric power from the heater power source 6 to the heater 5a. Further, the matching unit 43 and the filter box 45 are connected and unitized by the shield case 46, and are attached to the bottom of the discharge chamber 11. The shadow mask 46 is made of a conductive material such as aluminum or SUS. The shielding box 46 is provided with a conductive plate 47 made of a material such as copper connected to the power supply line 42, and is connected to a matching device (not shown) in the matching unit 43. By using the conductive plate 47, the contact area with the power supply line 42 can be increased, and the contact resistance can be reduced to reduce the current loss at the connection portion. As described above, the plasma processing apparatus 100 of the present embodiment is configured such that the matching unit 43 and the filter box 45 are connected and unitized by the shielding case 46, and are directly connected to the lower portion of the exhaust chamber 11 of the processing container 1. Therefore, the loss of the high-frequency electric power supplied from the high-frequency power source 44 to the electrode 7 can be reduced, so that the electric power consumption efficiency can be improved and the electric power can be stably supplied. Thereby, since the high frequency bias can be stably applied to the wafer W placed on the mounting table 5, the plasma generated in the processing container 1 can be stabilized, and the plasma processing can be performed uniformly.

As described above, the inner peripheral side of the cap assembly 27 is formed as a part of the cap assembly 27, and has a protruding portion 60 that abuts against the support portion 60A and the expanded projection portion 60B. In this manner, by integrally forming the lid assembly 27 and the protruding portion 60, thermal conductivity and conductivity can be ensured. The expanded protrusion 60B of the protruding portion 60 has an upper face 60B1, a front end face 60B2, and a lower face 60B3. Each of the protruding portions 60 is formed to face the plasma generating space S, and has a function of a counter electrode (second electrode) that is paired with the first electrode (the electrode 7 of the mounting table 5) with the plasma generating space S interposed therebetween. The main part. Specifically, the end portion (the portion A shown in the circle in the figure) of the abutting portion of the abutment supporting portion 60A and the microwave penetrating plate 28 of the cap assembly 27 in FIG. 2A is exposed around the protruding portion 60. The surface (ie, the surface of the support portion 60A and the upper portion 60B1 of the expanded protrusion 60B, the front end surface 60B2 and the lower surface 60B3) are abutted until the end portion of the support portion 60A is exposed (the circle shown in the figure) The portion B; the abutting end with the upper bushing 49a) has a portion that functions as a counter electrode. In the present embodiment, the inner peripheral surface of the annular cap assembly 27 of the portions A to B is exposed to the plasma generating space S to form an annular counter electrode. In this manner, by providing the annular member mainly forming the counter electrode with a space protruding toward the plasma, it is difficult to provide the counter electrode at a position directly above the mounting table 5 even if the microwave penetrating plate 28 is provided. In the RLSA type plasma processing apparatus 100, sufficient counter electrode surface area can still be ensured.

In the plasma processing apparatus 100 of the present embodiment, the portion having the function of the counter electrode facing the lower electrode can be defined as a conductive member having a ground potential and exposed to the plasma generating space S. Further, as will be described later, since the protective film 48 can be provided on the surface of the counter electrode, the term "exposed to the plasma generating space S" also includes a state in which it is covered by the protective film 48. Further, a more specific definition of the function of the counter electrode can be used as a reference. For example, the counter electrode is exposed to the plasma generating space S at a position higher than the wafer mounting surface of the mounting stage 5. The surface, and in the case where plasma is generated in the processing container 1, is a conductive member exposed to plasma having an electron density of 1 × 10 ¹¹ /cm ³ or more. However, the numerical values of the aforementioned electron density are merely illustrative, and the number is not particularly limited. For example, FIG. 3B is shown in the plasma processing apparatus 100, and when the processing pressure is changed to the gap G (the distance from the surface of the wafer W to the microwave penetration plate 28), the microwave penetration plate in the processing container 1 is measured. The result of electron density and electron temperature at the portion directly below the center of 28. Thus, since the electron density and electron temperature of the plasma generated in the processing container 1 also vary depending on the processing pressure or the gap G, it is preferable to adjust the surface area of the counter electrode in conjunction with the processing pressure or the gap G. Further, the gap G is preferably in the range of, for example, 50 mm to 150 mm, more preferably in the range of 70 mm to 120 mm.

The area of the portion of the plasma generating space S that has the function of the counter electrode (described as "the surface area of the counter electrode" in this patent specification) relative to the area of the electrode 7 of the mounting table 5 (in this patent specification) The area ratio of the "electrode area for biasing" is preferably 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and more preferably 2 or more and 4 or less. When the ratio of the surface area of the counter electrode to the area of the electrode for biasing (the surface area of the counter electrode/the area of the electrode for the bias) is less than 1, the vibration of the plasma potential becomes large, and it is impossible to stably stabilize in the processing container 1. The plasma is generated and the sputtering action is enhanced by the plasma near the counter electrode, so that the surface of the counter electrode is melted and becomes a cause of aluminum contamination. Further, the ratio of the surface area of the counter electrode to the area of the electrode for biasing (the surface area of the counter electrode/the area of the electrode for the bias) is preferably as large as possible. However, the upper limit may be set to 5 due to limitations in device size and structure. The ground is 4 or less. In addition, the area of the buried region of the electrode 7 of the mounting table 5 refers to an electrode 7 having an opening or a gap having a shape such as a mesh shape, a lattice shape, or a spiral shape, and including the opening and the gap portion as the same plane. The area of the planar area.

Preferably, the protruding amount of the front end portion of the protruding portion 60 having the opposite electrode function (the front end surface 60B2 of the expanding protruding portion 60B) is less than the position of the wafer W placed on the mounting table 5 (the position of the peripheral end of the wafer W) P _WE ). If the front end of the protruding portion 60 is closer to the inner side than the position P _{WE of the} peripheral end of the wafer W, the high-density and uniform plasma size generated in the processing container 1 will be smaller than the wafer size, so that the crystal is smaller. The plasma density at the peripheral portion of the circle W is reduced, and the processing content uniformity of the outer peripheral portion of the wafer W is adversely affected. On the other hand, at the side opposite to the front end portion (front end surface 62B2) of the protruding portion 60 having the counter electrode function (the side wall 1b side of the processing container 1), the abutting end with the side wall 1b becomes the base end portion, but In the present embodiment, it may be exposed to the plasma generation space S as long as it is in the middle portion B. In other words, in the present embodiment, the end portion of the 60B3 which is exposed to the protruding portion 60 of the counter electrode function is a contact point with the upper bushing 49a (portion B shown in Fig. 2A).

Further, the upper aspect 60B1 of the expansion protruding portion 60B facing the space S1 is disposed apart from the lower side of the microwave penetrating plate 28. That is, the expansion protrusion 60B protrudes toward the plasma generation space S and is spaced apart from the microwave penetration plate 28 by the space L1. In this manner, by spacing the microwave penetration plate 28 from the expansion projection 62 by the space L1, the effective area for microwave introduction of the microwave transmission plate 28 is not reduced, and the counter electrode can be sufficiently ensured. Surface area. Further, the space S1 is a part of the plasma generation space S, and plasma is generated also in the space S1, so that the plasma in the processing container 1 can be stably maintained. In contrast, as in the case of the conventional plasma processing apparatus, the gap L1 is not provided, but the microwave penetration plate 28 and the expansion protrusion 62 are placed in close contact with each other. If the surface area of the counter electrode in the processing container 1 is to be increased, It is necessary to increase the amount of protrusion toward the center side of the microwave penetrating plate 28. In this way, when the plasma is generated, since the effective area of the microwave penetrating plate 28 is reduced corresponding to the contact area with respect to the aspect 60B1 of the expansion protrusion 60B, the supply of the microwave electric power in the processing container 1 is caused. The amount of electricity will be reduced to produce plasma, or it will become unstable even if it is produced. In order to solve this problem, it is necessary to increase the processing container 1, but if the installation area is increased, the manufacturing cost of the device will also increase. Further, when the microwave penetrating plate 28 and the expanding projecting portion 60B are in close contact with each other, the counter electrode at the vicinity of the contact point of the microwave penetrating plate 28 and the counter electrode (that is, the front end of the expanding projecting portion 60B) The surface is sputtered in high-density plasma and is prone to metal contamination.

Preferably, the interval L1 is greater than the thickness of the sheath between the plasma generated directly below the microwave penetrating plate 28 and the microwave penetrating plate 28, and is preferably much greater than the distance of the electron mean free path. . For example, in the plasma processing apparatus 100 of FIG. 1, when the processing pressure is 6.7 Pa, the thickness of the sheath layer is about 0.25 mm when a high frequency bias voltage of 50 V is applied, and the average free traveling diameter of the electron is about 8 mm. . Therefore, it is preferable that the interval L1 is in the range of, for example, 10 mm or more and 30 mm or less, and more preferably in the range of 20 mm or more and 25 mm or less. When the interval L1 is within the above range, plasma can be stably generated in the processing container 1. When the interval L1 is less than 10 mm, the plasma in the space S1 may be unstable due to abnormal discharge, and particularly when the interval L1 is equal to or less than the thickness of the sheath, the plasma in the processing container 1 may become difficult. . On the other hand, when the interval L1 exceeds 30 mm, the expansion protruding portion 60B is too close to the electrode 7 of the mounting table 5, so that it is difficult to function as a counter electrode, and the heat of the mounting table 5 may be caused by the heat of the mounting table 5. The expansion protrusion 60B is subjected to thermal damage.

Further, similarly, in order to prevent the expansion protruding portion 60B from approaching the electrode 7 of the mounting table 5, the upper limit of the thickness of the expansion protruding portion 60B (that is, the distance between the upper surface 60B1 and the lower surface 60B3) L2 is preferably, for example, 20 mm. However, when the thickness L2 of the expanded projection 60B is too small, the effect as the counter electrode is lowered, so the lower limit of the thickness L2 is preferably, for example, 5 mm. Therefore, it is preferable that the thickness L2 of the expanded projection 60B is in the range of 5 mm or more and 20 mm or less, and more preferably in the range of 7 mm or more and 17 mm or less.

Further, in order to allow the expansion protruding portion 60B to function as a counter electrode and to prevent the expansion protruding portion 60B from being too close to the electrode 7 of the mounting table 5, it is preferable to extend the 60B3 under the expansion protruding portion 60B to the mounting table 5. The distance L3 (herein, the difference in height position between the two components) is, for example, in the range of 15 mm or more and 60 mm or less, and more preferably in the range of 20 mm or more and 25 mm or less.

Further, the plasma processing apparatus 100 of the present embodiment may be configured such that the gas introduction port 15a is provided at a position above the expanded protrusion 60B to supply the processing gas between the expansion protrusion 60B and the microwave penetration plate 28. Space S1. According to the above configuration, gas replacement and discharge in the space S1 directly under the microwave penetrating plate 28 can be promoted, and the process gas can be more easily activated. As a result, plasma can be efficiently generated as a whole in the space S1 directly below the microwave penetrating plate 28. Further, the space S1 is a part of the plasma generating space S. Further, as for the other effects, as shown in the later-described embodiment, when the processing gas is supplied to the space S1 directly below the microwave penetrating plate 28, for example, the plasma nitriding process is performed in the plasma processing apparatus 100. Since the discharge of oxygen released from the quartz microwave transmission plate 28 toward the outside of the processing container 1 can be promoted, it is possible to suppress a decrease in the nitrogen concentration in the nitride film formed. Further, the reason why oxygen is discharged from the microwave penetrating plate 28 is presumed to be two cases, one is that the oxygen originally present in the quartz microwave penetrating plate 28 is discharged; the other is that the plasma has been oxidized in the plasma processing apparatus 100 in the past. When the wafer W of the film is subjected to the plasma treatment, the oxygen discharged from the wafer W is temporarily adsorbed on the microwave penetrating plate 28, and the oxygen is discharged while performing the plasma nitriding treatment.

In the plasma processing apparatus 100 of the present embodiment, a protective film 48 is provided on the surface of the protruding portion 60 of the lid assembly 27 that constitutes the counter electrode. That is, since the cap assembly 27 is made of a metal such as aluminum or an alloy thereof, in order to prevent metal contamination or particles due to sputtering when exposed to the plasma, it is enlarged as shown in FIG. Covered with a protective film 48. The protective film 48 is formed on the surface of the abutting support portion 60A and the upper surface 60B1, the front end surface 60B2, and the lower surface 60B3 of the expanded protruding portion 60B. In view of the fact that the protective film 48 is melted to cause contamination and particles, the material of the protective film 48 is preferably ruthenium. The ruthenium may have a crystal structure such as single crystal germanium or polycrystalline germanium, or may be an amorphous germanium structure. Even if the protective film 48 is formed on the protruding portion 60, the function as a counter electrode can be maintained to stably generate plasma and perform uniform plasma treatment. The protective film 48 can effectively form a high-frequency current path that flows from the mounting table 5 through the plasma generating space S and through the counter electrode (the protruding portion 60) to the cap assembly 27, thereby suppressing short-circuit or abnormal discharge at other portions. The surface of the counter electrode is protected from oxidation or sputtering by the plasma to suppress contamination due to the constituent material (metal such as aluminum) of the counter electrode. Further, in the case where the ruthenium film is used as the protective film 48, even if the ruthenium film is oxidized by the plasma oxidation to form a ruthenium dioxide film (SiO ₂ film), it is very thin and has a dielectric constant and a resistivity. Since the material is multiplied by a small amount of material, the current path which flows from the mounting table 5 across the plasma generating space S toward the counter electrode (the lid assembly 27) is less hindered, and an appropriate high-frequency current path can be stably maintained.

Further, the ruthenium film as the protective film 48 is preferably a low-resistivity film having a small porosity and a dense film in the film. Since the volume resistivity is also increased when the porosity in the film is large, for example, the porosity is in the range of 1 to 10%, and the volume resistivity is in the range of 5 × 10 ⁴ to 5 × 10 ⁵ Ω ‧ cm ² good. Such a ruthenium film is preferably formed by, for example, a plasma spray method. Further, the thickness of the protective film 48 is preferably in the range of, for example, 10 to 800 μm, more preferably in the range of 50 to 500 μm, and desirably in the range of 50 to 150 μm. When the thickness of the protective film 48 is less than 10 μm, sufficient protective effect cannot be obtained, and if it exceeds 800 μm, cracks, peeling, and the like are likely to occur due to stress.

The protective film 48 may be formed by a thin film forming technique such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition), in addition to, for example, a plasma spray method. Among them, a sputtering method which is inexpensive, easy to process, and capable of forming the protective film 48 which is easy to control within a proper range by forming the aforementioned porosity and volume resistivity is preferable. The spraying method includes flame spraying, arc spraying, laser spraying, plasma spraying, etc., but it is preferable to form a plasma jet of a high-purity film with good controllability. Further, examples of the plasma spray method include an atmospheric piezoelectric slurry spray method and a vacuum plasma spray method, and any of them can be used.

Further, the protective film 48 may be made of TiN, Y ₂ O ₃ , Al ₂ O ₃ , SiO ₂ or the like instead of ruthenium.

Further, according to the plasma processing apparatus 100 of the present embodiment, a cylindrical bush made of quartz is provided on the inner circumference of the processing container 1. The structure of the bushing includes: an upper bushing 49a mainly serving as a first insulating plate covering the inner surface of the upper portion of the processing container 1, and a lower bushing 49b continuously provided with the upper bushing 49a, and mainly serving as a covering processing container 1 The second insulating plate on the inner surface of the lower portion. The upper bushing 49a and the lower bushing 49b function to prevent the wall of the processing container 1 from coming into contact with the plasma to prevent metal contamination caused by the constituent material of the processing container 1, and to prevent the side wall from the mounting table 5 toward the processing container 1. A high frequency current short circuit or abnormal discharge of 1b occurs. It is assumed that the thickness of the lower bushing 49b disposed at a position close to the space between the mounting table 5 is much larger than that of the upper bushing 49a. The thickness of the upper bushing 49a and the lower bushing 49b may be set as long as it does not cause a short-circuit or abnormal discharge of a high-frequency current, and the impedance is considered. Preferably, it is within a thickness range of, for example, 2 mm to 30 mm, and the lower bushing 49b is set to be thicker than the upper bushing 49a.

Further, the lower bushing 49b is provided so as to cover at least a part of the inner surface of the processing container 1 and the exhaust chamber 11 at a position lower than the height of the mounting table 5 in which the electrode 7 is buried, and preferably covers almost the entire portion. This is because the distance between the mounting table 5 and the processing container 1 is the shortest at the lower portion of the mounting table 5, and the abnormal discharge at the portion is prevented. Further, the upper bushing 49a and 49b of the lower portion of the liner material although preferably quartz, but may also be used _{Al 2 O 3, AlN, Y2O} 3 like ceramic dielectric. Further, the upper bushing 49a and the lower bushing 49b may be formed by coating the above materials. Further, for example, the surfaces of the aluminum upper bushing 49a and the lower bushing 49b may be coated with, for example, a SiO ₂ film by a plasma spray method.

Each component of the plasma processing apparatus 100 is configured to be connected to a control unit 50 having a computer and controlled. For example, as shown in FIG. 4, the control unit 50 includes a process controller 51 having a CPU, a user interface 52 connected to the process controller 51, and a memory unit 53. The process controller 51 is used to coordinate and control various components related to process conditions such as temperature, pressure, gas flow rate, microwave output, and high-frequency electric power for applying bias voltage (for example, a heater). A control mechanism of the power source 6, the gas supply device 16, the exhaust device 24, the microwave generating device 39, the high-frequency power source 44, and the like.

The user interface 52 has a keyboard for inputting an operation command or the like by the process manager for managing the plasma processing apparatus 100, or a display for visually displaying the operation state of the plasma processing apparatus 100. Further, the storage unit 53 stores a recipe for recording a control program (software) or processing condition data for realizing various processes executed by the plasma processing apparatus 100 by the control of the process controller 51.

In addition, any process recipe can be called from the memory unit 53 according to the instruction from the user interface 52, and the process controller 51 can be implemented to be processed by the plasma processing apparatus 100 under the control of the process controller 51. The desired treatment is carried out inside the container 1. Moreover, the process recipes for the control program or processing condition data and the like can be stored in a state of a computer readable memory medium (for example, a CD-ROM, a hard disk, a floppy disk, a flash memory, a DVD, a Blu-ray disk). . Furthermore, the process recipe can also be transferred and used from other devices via, for example, a dedicated line.

In the plasma processing apparatus 100 of the present invention having the above-described configuration, the base film or the substrate (wafer W) can be subjected to plasma oxidation treatment without causing damage at a low temperature of, for example, room temperature (about 25 ° C) or more and 600 ° C or less. Or plasma nitriding treatment. Further, since the plasma processing apparatus 100 is excellent in plasma uniformity, process uniformity can be achieved even for a large-sized wafer W (subject to be processed).

Next, the operation of the plasma processing apparatus 100 will be described. First, the wafer W is carried into the processing container 1 and placed on the mounting table 5. Further, the processing gas is introduced into the processing container 1 from the gas supply device 16 through the gas supply passage 12, the annular passage 13, and the gas introduction port 15a. As the processing gas, in addition to a rare gas such as Ar, Kr, He or the like, when the plasma is oxidized, a oxidizing gas such as O ₂ , N ₂ O, NO, NO ₂ , CO ₂ or the like is supplied at a specific flow rate, or a plasma is used. In the case of the nitriding treatment, a nitrogen-containing gas such as N ₂ or NH _{3 is} supplied at a specific flow rate. In addition, in the case of plasma oxidation treatment, H ₂ may be added as needed.

Then, the microwave from the microwave generating device 39 is conducted to the waveguide 37 via the matching circuit 38, and sequentially passes through the rectangular waveguide 37b, the mode converter 40, and the coaxial waveguide 37a, and is supplied to the plane via the inner conductor 41. The antenna 31 is radiated from the slot 32 of the planar antenna 31 to the processing container 1 via the microwave penetrating plate 28. In the middle, the microwave system propagates in the TE mode in the rectangular waveguide 37b, and the TE mode microwave is converted into the TEM mode by the mode converter 40, and propagates toward the planar antenna 31 in the coaxial waveguide 37a. By radiating the microwaves from the planar antenna 31 through the microwave penetrating plate 28 into the processing container 1, an electromagnetic field can be formed in the processing container 1 to plasma the processing gas.

The microwave is formed by being radiated from a plurality of slots 32 of the planar antenna 31 to form a high density (about 1 × 10 ¹⁰ to 5 × 10 ¹² /cm ³ ) and about 1.5 eV or less near the wafer W. Low electron temperature plasma. Therefore, by the action of the plasma on the wafer W, the plasma damage can be suppressed.

Further, in the present embodiment, when the plasma processing is performed, the high-frequency electric power is supplied from the high-frequency power source 44 to the electrode 7 of the mounting table 5 at a specific frequency. The frequency of the high-frequency electric power supplied from the high-frequency power source 44 is preferably in the range of, for example, 100 kHz to 60 MHz, and more preferably in the range of 400 kHz to 13.5 MHz. The negative bias can be efficiently applied to the mounting table 5 using the high frequency electric power frequency within the aforementioned range.

High frequency electric power lines such as electric power density per unit area of wafer W is supplied preferably in the range of ² or less of 0.2W / cm ² or more 2.3W / cm, or less in the range of ² 0.35W / cm ² or more 1.2W / cm Better supply. The negative bias voltage can be efficiently applied to the mounting table 5 by using the high frequency electric power density within the above range.

Further, the high-frequency electric power is preferably in the range of 200 W or more and 2000 W or less, and more preferably in the range of 300 W or more and 1200 W or less. The negative bias can be efficiently applied to the stage 5 by using the high frequency electric power within the above range.

The high-frequency electric power supplied to the electrode 7 of the mounting table 5 has a function of maintaining the low electron temperature of the plasma and attracting the ion species in the plasma toward the wafer W. Therefore, by supplying high-frequency electric power to the electrode 7 and applying a bias voltage to the wafer W, the speed of the plasma oxidation treatment or the plasma nitridation treatment can be increased, and the processing uniformity in the wafer surface can be improved.

At this time, the high-frequency electric power is transmitted from the high-frequency power source 44 via the unitized high-frequency electric power introduction unit (the matching unit 43 and the conductive plate 47 in the shield case 46) and the power supply line 42, and is high in a state where electric power loss is small. It is efficiently supplied to the electrode 7 of the mounting table 5. The high-frequency electric power supplied to the electrode 7 is propagated toward the cap assembly 27 having the protruding portion 60 (the main portion having the function of the counter electrode from the mounting table 5 via the plasma generating space S), via the side wall 1b of the processing container 1. Then, a high-frequency current path (RF return circuit) that is transmitted to the ground end of the high-frequency power source 44 is formed via the wall of the exhaust chamber 11. In the present embodiment, by providing the expansion protruding portion 60B, it is possible to suppress the vibration of the plasma potential (Vp), thereby stably generating plasma in the processing container 1, and preventing the counter electrode from being caused by the sputtering action of the plasma. The surface is dissolved and becomes the cause of metal contamination.

Further, since the exposed surface of the protruding portion 60 (opposing electrode) facing the plasma generating space S is provided with the conductive protective film 48 (the SiO ₂ film formed by oxidation of the ruthenium film or ruthenium), the counter electrode can be protected. The surface of the high-frequency current path through which the high-frequency current flowing from the mounting table 5 to the lid assembly 27 (opposing electrode) is normally prevented from being hindered. Further, since the inner liner of the processing container 1 adjacent to the protective film 48 is provided with the upper bushing 49a and the thickness of the lower bushing 49b, it is possible to reliably suppress short-circuiting or abnormal discharge to the portions. That is to say, by the protective film 48, abnormal discharge can be suppressed and metal contamination can be prevented.

As described above, the plasma processing apparatus 100 of the present embodiment can secure a sufficient counter electrode surface area by the expansion protrusion 60B of the protruding portion 60 (opposing electrode), and by forming an appropriate high-frequency current path, The electric power consumption efficiency of the bias high-frequency electric power supplied to the electrode 7 on which the wafer W is placed is increased. Further, since the space S1 is formed between the expansion protruding portion 60B and the microwave penetrating plate 28, and the counter electrode is protruded toward the plasma generating space S, the plasma can be stably generated in the plasma generating space S and the space S1. . Moreover, abnormal discharge can be prevented, and process efficiency and stabilization can be achieved. Further, since the expansion protruding portion 60B is provided from the microwave penetration plate 28 with the interval L1 therebetween, the effective area of the microwave penetration plate 28 is not reduced, and the microwave electric power can be sufficiently introduced and the inside of the processing container 1 can be The resulting plasma is stabilized.

[Second Embodiment]

Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to Fig. 5. In addition, the plasma processing apparatus 101 of the second embodiment is the same as the plasma processing apparatus 100 of the first embodiment except for the specific portions thereof, and therefore the description of the entire configuration is omitted (Fig. 1, Fig. 3, and Fig. 4). In the fifth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and their description will be omitted.

In the plasma processing apparatus 101 of the present embodiment, the inner peripheral side of the lid assembly 27 is formed with a protruding portion 61 as a part of the lid assembly 27. In this way, by integrally molding the cap assembly 27 and the protruding portion 61, thermal conductivity and conductivity can be ensured. The protruding portion 61 has an abutting support portion 61A and an expanded protruding portion 61B. The expanded protrusion 61B of the protruding portion 61 has an upper surface 61B1, a front end surface 61B2, and a lower surface 61B3. The protruding portion 61 is formed to face the plasma generating space S, and is mainly composed of a counter electrode (second electrode) that is paired with the first electrode (electrode 7 of the mounting table 5) with the plasma generating space S interposed therebetween. section. Specifically, in Fig. 5, the surface of the abutting portion of the abutment portion 61A of the cap assembly 27 and the microwave penetrating plate 28 (the portion A shown in the circle in the figure) surrounds the surface exposed by the protruding portion 61. (that is, abutting the surface of the support portion 61A and the upper surface 61B1 of the expanded projection 61B, the front end surface 61B2 and the lower surface 61B3) until the end portion of the support portion 61A is exposed (the circle in the figure) The inner peripheral surface of the display portion B; the abutting end with the upper bushing 49a has a function of the counter electrode function. In the present embodiment, the surfaces of the portions A to B are exposed to the plasma generation space S to form an annular counter electrode. In this manner, by providing the annular member mainly forming the counter electrode with a space protruding toward the plasma, it is difficult to provide the counter electrode at a position directly above the mounting table 5 even if the microwave penetrating plate 28 is provided. In the RLSA mode microwave plasma processing apparatus 101, sufficient surface area of the counter electrode can still be ensured.

Further, in the plasma processing apparatus 101 of the present embodiment, the surface of the expanded protruding portion 61B of the protruding portion 61 having the opposite electrode function (that is, the upper surface 61B1, the front end surface 61B2, and the lower surface 61B3) is mainly formed with irregularities. The cross-sectional shape is such that the surface area of the counter electrode can be sufficiently ensured. As described above, by designing the shape of the expanded protrusion 61B constituting the counter electrode, the area of the counter electrode can be sufficiently ensured in the limited space in the processing container 1. In the present embodiment, the surface potential of the counter electrode exposed to the plasma generating space S can also suppress the vibration of the plasma potential, thereby generating a stable plasma in the processing container 1, and weakening the plasma near the counter electrode. The sputtering effect is preferably such that the area ratio of the electrode area for the bias voltage is 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and more preferably 2 or more and 4 or less. Within the scope. Further, the aforementioned area ratio in the plasma processing apparatus 101 shown in Fig. 5 is about 5.

Moreover, it is preferable that the amount of protrusion of the front end surface 61B2 of the protruding portion 61 having the counter electrode function is not at the position P _WE of the peripheral end of the wafer W placed on the mounting table 5. If the front end of the protruding portion 61 is closer to the inner side than the position P _{WE of the} peripheral end of the wafer W, the high-density plasma region generated in the processing container 1 will be smaller than the wafer size, so that the wafer W periphery The plasma density of the portion is reduced, and the processing content uniformity of the outer peripheral portion of the wafer W is adversely affected. On the other hand, at the side opposite to the front end portion (front end surface 61B2) of the protruding portion 61 having the counter electrode function (the side wall 1b side of the processing container 1), the abutting end with the side wall 1b becomes the base end portion, but In the present embodiment, it may be exposed to the plasma generation space S as long as it is in the middle portion B. In other words, in the present embodiment, the lower end portion of the abutting support portion 61A having the protruding electrode function 61 is formed to be in contact with the upper bushing 49a (shown as the portion B in Fig. 5). ).

Further, the upper surface 61B1 of the expansion protruding portion 61B facing the space S1 is disposed apart from the lower side of the microwave penetrating plate 28. That is, the expansion protruding portion 61B protrudes toward the plasma generation space S and is spaced apart from the microwave penetration plate 28 by the space L1. In this manner, by spacing the microwave penetration plate 28 and the expansion projection 61B at intervals L1, the effective area for microwave introduction of the microwave penetration plate 28 is not reduced, and the counter electrode can be sufficiently ensured. Surface area. Further, the space S1 is a part of the plasma generation space S, and plasma is generated also in the space S1, so that the plasma treatment of the wafer W can be made uniform. In contrast, the gap L1 is not provided, but the microwave penetration plate 28 and the expansion protrusion 61B are placed in close contact with each other. If the surface area of the counter electrode in the processing container 1 is to be increased, the microwave penetration plate must be increased. 28 The amount of protrusion on the center side. As a result, when the plasma is generated, since the effective area of the microwave penetrating plate 28 is reduced corresponding to the expansion projecting portion 61B, the supply amount of the microwave electric power in the processing container 1 is reduced, and plasma cannot be generated. Or even if it occurs, it will become unstable. In order to solve this problem, it is necessary to increase the processing container 1, but if the installation area is increased, the manufacturing cost of the device will also increase.

Preferably, the interval L1 is greater than the thickness of the sheath between the plasma generated directly below the microwave penetrating plate 28 and the microwave penetrating plate 28, and is preferably sufficiently greater than the distance of the electron mean free path. It is preferable that the interval L1 is in the range of, for example, 10 mm or more and 30 mm or less, and more preferably in the range of 20 mm or more and 25 mm or less. When the interval L1 is less than 10 mm, the plasma in the space S1 may be unstable due to abnormal discharge, and particularly when the interval L1 is equal to or less than the thickness of the sheath, the plasma in the processing container 1 may become difficult. . On the other hand, when the interval L1 exceeds 30 mm, the expansion protruding portion 61B is too close to the electrode 7 of the mounting table 5, so that it is difficult to function as a counter electrode, and the heat of the mounting table 5 may be caused. The expansion protrusion 61B is subjected to thermal damage.

Further, similarly, in order to prevent the expansion protruding portion 61B from being too close to the electrode 7 of the mounting table 5, it is preferable that the upper limit of the thickness of the expansion protruding portion 61B (that is, the distance between the upper surface 61B1 and the lower surface 61B3) L2 is For example 20mm. However, if the thickness L2 of the expanded projection 61B is too small, the effect as the counter electrode is lowered, so the lower limit of the thickness L2 is preferably, for example, 5 mm. Therefore, it is preferable that the thickness L2 of the expansion protruding portion 61B is in the range of 5 mm or more and 20 mm or less, and more preferably in the range of 7 mm or more and 17 mm or less.

Further, in order to allow the expansion protruding portion 61B to function as a counter electrode and to prevent the expansion protruding portion 61B from being too close to the electrode 7 of the mounting table 5, it is preferable to extend the projection portion 61B from the lower surface 61B3 to the mounting table 5. The distance L3 (herein, the difference in height position between the two components) is, for example, in the range of 15 mm or more and 60 mm or less, and more preferably in the range of 20 mm or more and 25 mm or less.

Further, the plasma processing apparatus 101 of the present embodiment is configured such that the gas introduction port 15a is provided at the abutting support portion 61A at a position above the expanded protrusion 61B, and the processing gas is supplied to the expansion protrusion 61B and the microwave. The space S1 between the transparent plates 28. According to the above configuration, gas replacement and discharge in the space S1 directly under the microwave penetrating plate 28, which is a part of the plasma generating space S, can be promoted, and the processing gas can be more easily activated. As a result, plasma can be efficiently generated as a whole in the space S1 directly below the microwave penetrating plate 28. Further, regarding other effects, by supplying the processing gas to the space S1 directly below the microwave penetrating plate 28, when performing the plasma nitriding process, for example, in the plasma processing apparatus 101, it is possible to promote the production from quartz. Since the microwaves are vented by the oxygen emitted from the plate 28, the decrease in the nitrogen concentration in the nitride film formed is suppressed.

Further, in the present embodiment, the protective film 48 is also provided on the surface on which the protruding portion 61 is exposed. The protective film 48 prevents the protrusion 61 from being splashed to cause metal contamination or particles when exposed to the plasma. Even if the protective film 48 is formed on the protruding portion 60, the function as a counter electrode can be maintained to stably generate plasma and perform uniform plasma treatment.

Further, the concavo-convex shape of the expansion protruding portion 61B is not limited to the wavy shape shown in FIG. 5, and may be any shape such as a groove shape or a hole shape, and may have a shape that can increase the surface area. However, from the viewpoint of preventing abnormal discharge or fine particles from occurring on the surface of the expanded projection 61B facing the plasma generating space S, as shown in Fig. 5, it is preferable to form the wave shape in which the corner portion is rounded. Further, the entire expansion protruding portion 61B does not have to be formed in a concavo-convex shape. For example, it may be provided only in the upper aspect 61B1 of the expansion projection 61B or the lower aspect 61B3.

Other configurations and effects of this embodiment are the same as those of the first embodiment.

[Third embodiment]

Next, a plasma processing apparatus according to a third embodiment of the present invention will be described with reference to Fig. 6. In the plasma processing apparatus 102 of the third embodiment, the plasma processing apparatus 100 of the first embodiment is the same as the plasma processing apparatus 100 of the first embodiment, and therefore the entire configuration is omitted (Fig. 1, Fig. 3, and Fig. 4). In FIG. 6 , the same components as those in FIG. 2A are denoted by the same reference numerals, and description thereof will be omitted.

In the plasma processing apparatus according to the first and second embodiments, the protruding portions 60 and 61 of the cap unit 27 are provided with the expansion protruding portions 60B and 61B, and are the main portions having the function of the counter electrode, but the electric power of the embodiment is In the slurry processing apparatus 102, an expansion protrusion 62 that protrudes inward as a part of the processing container 1 is provided on the upper portion of the processing container 1, to increase the area of the functional portion having the counter electrode. Thereby, the processing container 1 and the expansion protruding portion 62 are integrally formed, and thermal conductivity and conductivity can be ensured. The expansion projection 62 is electrically connected to the abutment support portion 60' for supporting the microwave penetration plate 28 at the cover assembly 27.

The expansion protrusion 62 is provided at the upper end of the side wall 1b of the processing container 1. The expansion protruding portion 62 includes an abutting portion 62A that abuts against the abutting support portion 60' of the cap assembly 27, and an exposed portion 62B that has an exposed upper surface 62B1, a distal end surface 62B2, and a lower surface 62B3. The abutting support portion 60' and the expansion projecting portion 62 are formed to face the plasma generating space S, and are opposed to the first electrode (the electrode 7 of the mounting table 5) with the plasma generating space S interposed therebetween. The main part of the electrode (second electrode) function. Specifically, in FIG. 6 , from the abutting portion end portion of the abutment supporting portion 60 ′ of the cap assembly 27 and the microwave penetrating plate 28 (the portion A shown in the circle in the drawing), the abutting supporting portion 60 ′ The exposed surface and the surface of the expansion protrusion 62 (that is, the upper surface 62B1, the front end surface 62B2 and the lower surface 62B3 of the expansion protrusion 62 are exposed) until the end portion of the expansion protrusion 62 is exposed (in the figure) The inner peripheral surface of the portion B of the loop; the abutting end with the upper bushing 49a has a function of the counter electrode function. In the present embodiment, the surfaces of the portions A to B are exposed to the plasma generation space S to form an annular counter electrode. Thereby, the counter electrode can be formed by a plurality of components (the cap assembly 27 and the processing container 1) having the surface facing the plasma generating space S. Then, by arranging the annular component mainly forming the counter electrode toward the plasma generating space, even if it is provided with the microwave penetrating plate 28, it is difficult to provide the RLSA of the counter electrode at the position directly above the mounting table 5. In the manner of the microwave plasma processing apparatus 102, sufficient surface area of the counter electrode can still be ensured. Further, in the present embodiment, since the expansion protruding portion 62 (which may be said to be an expanded portion of the counter electrode) is provided on the upper portion of the processing container 1, the surface of the wafer W placed on the mounting table 5 is required to be microwaved. The case where the distance of the penetrating plate 28 (gap G; refer to Fig. 1) is reduced is very effective.

In the present embodiment, the surface potential of the counter electrode exposed to the plasma generating space S can also suppress the vibration of the plasma potential, thereby generating a stable plasma in the processing container 1, and weakening the plasma near the counter electrode. The sputtering effect is preferably such that the area ratio of the electrode area for the bias voltage is 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and more preferably 2 or more and 4 or less. Within the scope.

Moreover, it is preferable that the amount of protrusion of the front end surface 62B2 of the expansion protruding portion 62 having the counter electrode function is not at the position P _WE of the peripheral end of the wafer W placed on the mounting table 5. If the front end of the expansion protrusion 62 is closer to the inner side than the position P _{WE of the} peripheral end of the wafer W, the high-density plasma area generated in the processing container 1 will be smaller than the wafer size, so that the wafer W The plasma density at the peripheral portion is reduced, and the processing content uniformity of the outer peripheral portion of the wafer W is adversely affected. On the other hand, at the side opposite to the front end portion (front end surface 62B2) of the expansion protruding portion 62 having the counter electrode function (the side wall 1b side of the processing container 1), the corner portion bent from the side wall 1b becomes the base end portion, but In the present embodiment, it may be exposed to the plasma generation space S as long as it is in the middle portion B. In other words, in the present embodiment, the end portion of the expanded projection portion 62 having the counter electrode function is formed to be in contact with the upper bushing 49a (shown as a portion B in Fig. 6).

Further, the upper surface 62B1 of the expansion protruding portion 62 facing the space S1 is disposed apart from the lower side of the microwave penetrating plate 28. That is, the expansion protrusion 62 protrudes toward the plasma generation space S and is spaced apart from the microwave penetration plate 28 by the space L1. In this manner, by spacing the microwave penetration plate 28 from the expansion projection 62 by the space L1, the effective area for microwave introduction of the microwave transmission plate 28 is not reduced, and the counter electrode can be sufficiently ensured. Surface area. Further, the space S1 is a part of the plasma generation space S, and plasma is generated also in the space S1, so that the wafer W can be plasma-processed uniformly. In contrast, the gap L1 is not provided but the microwave penetrating plate 28 and the expanding protrusion 62 are closely arranged. If the surface area of the counter electrode in the processing container 1 is to be increased, it is necessary to increase toward the center of the microwave penetrating plate 28. The amount of protrusion on the side. In this way, when the plasma is generated, since the effective area of the microwave penetrating plate 28 is reduced corresponding to the contact area with respect to the upper portion 62B1 of the expanding projection 62, the supply of microwave electric power in the processing container 1 is caused. The amount of electricity will be reduced to produce plasma, or it will become unstable even if it is produced. In order to solve this problem, it is necessary to increase the processing container 1, but if the installation area is increased, the manufacturing cost of the device will also increase.

Preferably, the interval L1 is greater than the thickness of the sheath between the plasma generated immediately below the microwave penetrating plate 28 and the microwave penetrating plate 28. Preferably, the interval L1 is in the range of, for example, 10 mm or more and 30 mm or less. More preferably, it is in the range of 20 mm or more and 25 mm or less. When the interval L1 is less than 10 mm, the plasma in the space S1 may be unstable due to abnormal discharge, and particularly when the interval L1 is equal to or less than the thickness of the sheath, the plasma in the processing container 1 may become difficult. . On the other hand, when the interval L1 exceeds 30 mm, the expansion protruding portion 62 is too close to the electrode 7 of the mounting table 5, so that it is difficult to function as a counter electrode, and the heat of the mounting table 5 may be caused. The expansion tab 62 is subject to thermal damage.

Further, similarly, in order to prevent the expansion protruding portion 62 from being too close to the electrode 7 of the mounting table 5, the upper limit of the thickness of the expansion protruding portion 62 (that is, the distance between the upper surface 62B1 and the lower surface 62B3) L2 is preferably, for example, 20 mm. However, if the thickness L2 of the expanded projection 62 is too small, the effect as the counter electrode is lowered, so the lower limit of the thickness L2 is preferably, for example, 5 mm. Therefore, it is preferable that the thickness L2 of the expansion protruding portion 62 is in the range of 5 mm or more and 20 mm or less, and more preferably in the range of 7 mm or more and 17 mm or less.

Further, in order to allow the expansion protruding portion 62 to function as a counter electrode and to prevent the expansion protruding portion 62 from being too close to the electrode 7 of the mounting table 5, it is preferable to expand the protruding portion 62 from the lower surface 62B3 to the mounting table 5. The distance L3 (herein, the difference in height position between the two components) is, for example, in the range of 15 mm or more and 60 mm or less, more preferably in the range of 20 mm or more and 25 mm or less.

Further, the plasma processing apparatus 102 of the present embodiment is configured such that the gas introduction port 15a is provided at the abutting support portion 60' at a position above the expanded protrusion 62 to supply the processing gas to the expansion protrusion 62 and the microwave. The space S1 between the plates 28 is penetrated. According to the above configuration, gas replacement and discharge in the space S1 directly under the microwave penetrating plate 28, which is a part of the plasma generating space S, can be promoted, and the processing gas can be more easily activated. As a result, plasma can be efficiently generated as a whole in the space S1 directly below the microwave penetrating plate 28. Further, regarding other effects, by supplying the processing gas to the space S1 directly under the microwave penetrating plate 28, when performing the plasma nitriding process, for example, in the plasma processing apparatus 102, it is possible to promote the production from quartz. The microwave passes through the discharge of oxygen released from the plate 28, so that the decrease in the nitrogen concentration in the nitride film formed is suppressed.

In the plasma processing apparatus 102 of the present embodiment, a protective film 48 is provided on the surface of the abutting support portion 60' and the expanded projection portion 62 which constitute the counter electrode. That is, as shown in Fig. 6, the exposed surface of the abutting support portion 60' of the aluminum cap assembly 27 exposed to the plasma is covered with the protective film 48. Further, the exposed surface of the expanded projection 62 provided in the processing container 1 exposed to the plasma is also covered with the protective film 48. The protective film 48 prevents metal contamination or particles from being splashed when the abutting support portion 60' and the expanded projection 62 are exposed to the plasma. Even if the protective film 48 is formed on the abutting support portion 60' or the expanded projection portion 62, the function as a counter electrode can be maintained to stably generate plasma and perform uniform plasma treatment.

Other configurations and effects of this embodiment are the same as those of the first embodiment.

[Fourth embodiment]

Next, a plasma processing apparatus according to a fourth embodiment of the present invention will be described with reference to Fig. 7. In addition, the plasma processing apparatus 103 of the fourth embodiment is the same as the first embodiment except for the specific portions thereof, and therefore the description of the overall configuration (the first drawing, the third drawing, and the fourth drawing) is omitted, and the seventh embodiment is omitted. In the drawings, the same components as those in FIG. 2A are denoted by the same reference numerals, and description thereof will be omitted.

In the plasma processing apparatus 103 of the present embodiment, the annular auxiliary electrode assembly is additionally provided to the abutment supporting portion 60' of the cap unit 27, and the expanded protruding portion 63 is provided. In this way, part or all of the counter electrode can also be formed by additionally providing components. By making the expansion projection 63 different from the assembly of the lid assembly 27 or the processing container 1, it can be easily replaced as a consumable. The expansion protrusion 63 has an upper surface 63a, a front end surface 63b, and a lower surface 63c.

The auxiliary electrode assembly constituting the expansion protruding portion 63 is not particularly limited as long as it is a conductor. For example, in addition to a metal material such as aluminum or an alloy thereof or stainless steel, for example, tantalum or the like can be used. In particular, in the case where the expansion protruding portion 63 is formed by ruthenium, it is advantageous since the surface does not need to be provided with a protective film. The expansion projection 63 can be fixed to the inner circumferential surface of the abutment support portion 60' of the cap assembly 27 by any fixing direction such as a screw (not shown).

In the plasma processing apparatus 103 of the present embodiment, the expansion protruding portion 63 is formed to face the plasma generation space S, and is paired with the first electrode (the electrode 7 of the mounting table 5) with the plasma generation space S interposed therebetween. The main part of the counter electrode (second electrode) function. Specifically, from the end of the abutting portion of the abutment supporting portion 60' of the cap assembly 27 and the microwave penetrating plate 28 (the portion A shown in the circle), the abutting abutting portion 60' is The exposed surface and the surface of the expansion protrusion 63 (that is, the upper surface 63a, the front surface 63b and the lower surface 63c of the expansion protrusion 63 are exposed) until the end portion of the contact portion 60' is exposed (Fig. The inner peripheral surface of the portion B) shown in the middle ring has a function of the counter electrode function. In the present embodiment, the surfaces of the portions A to B are exposed to the plasma generation space S to form an annular counter electrode. Thereby, the counter electrode can be formed by a plurality of components (the cap assembly 27 and the auxiliary electrode assembly of the expansion protrusion 63) having the surface facing the plasma generating space S. Then, by causing the annular member mainly forming the counter electrode to protrude toward the plasma generating space S, it is difficult to provide the counter electrode at a position directly above the mounting table 5 even if the microwave penetrating plate 28 is provided. In the RLSA mode microwave plasma processing apparatus 103, sufficient surface area of the counter electrode can still be ensured.

In the present embodiment, by additionally providing the expansion protruding portion 63 by the abutment supporting portion 60' of the cap assembly 27, the surface area of the portion having the function of the counter electrode can be sufficiently ensured. In this manner, by constituting the counter electrode by a combination of a plurality of components, the area of the counter electrode can be sufficiently ensured in the limited space in the processing container 1. In the present embodiment, the surface potential of the counter electrode exposed to the plasma generating space S can also suppress the vibration of the plasma potential, thereby generating a stable plasma in the processing container 1, and weakening the plasma near the counter electrode. The sputtering effect is preferably such that the area ratio of the electrode area for the bias voltage is 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and more preferably 2 or more and 4 or less. Within the scope.

Further, it is preferable that the protruding length of the tip end portion (front end surface 63b) of the expanding projection portion 63 having the counter electrode function is not at the position P _WE of the peripheral end of the wafer W placed on the mounting table 5. If the front end of the expansion protrusion 63 is closer to the inner side than the position P _{WE of the} peripheral end of the wafer W, the high-density plasma area generated in the processing container 1 will be smaller than the wafer size, so that the wafer W The plasma density at the peripheral portion is reduced, and the processing content uniformity of the outer peripheral portion of the wafer W is adversely affected. On the other hand, at the opposite side of the front end portion (front end surface 63b) of the expansion projection portion 63, the joint portion between the expansion projection portion 63 and the abutment support portion 60 is exposed to the plasma generation space S up to the portion B. . In other words, in the present embodiment, the end portion of the abutting support portion 60' having the counter electrode function is formed to be in contact with the upper bushing 49a (shown as a portion B in Fig. 7).

Further, the upper portion 63a of the expanded projection 63 is disposed apart from the lower side of the microwave penetrating plate 28. That is, the expansion protrusion 63 protrudes toward the plasma generation space S and is spaced apart from the microwave penetration plate 28 by the space L1. In this manner, by spacing the microwave penetration plate 28 from the expansion projection 63 by the space L1, the effective area for microwave introduction of the microwave penetration plate 28 is not reduced, and the counter electrode can be sufficiently ensured. Surface area. Further, the space S1 is a part of the plasma generation space S, and plasma is generated also in the space S1, so that the plasma treatment of the wafer W can be made uniform. In contrast, the interval L1 is not provided, but the microwave penetration plate 28 and the expansion protrusion 63 are closely arranged. If the surface area of the counter electrode in the processing container 1 is to be increased, the microwave penetration plate must be increased. 28 The amount of protrusion on the center side. As a result, when the plasma is generated, since the effective area of the microwave penetrating plate 28 is reduced corresponding to the contact area with respect to the upper face 63b of the expanded protrusion 63, the supply of microwave electric power in the processing container 1 is caused. The amount of electricity will be reduced to produce plasma, or it will become unstable even if it is produced. In order to solve this problem, it is necessary to increase the processing container 1, but if the installation area is increased, the manufacturing cost of the device will also increase.

Preferably, the interval L1 is greater than the thickness of the sheath between the plasma generated immediately below the microwave penetrating plate 28 and the microwave penetrating plate 28. Preferably, the interval L1 is in the range of, for example, 10 mm or more and 30 mm or less. More preferably, it is in the range of 20 mm or more and 25 mm or less. When the interval L1 is less than 10 mm, the plasma in the space S1 may be unstable due to abnormal discharge, and particularly when the interval L1 is equal to or less than the thickness of the sheath, the plasma in the processing container 1 may become difficult. . On the other hand, when the interval L1 exceeds 30 mm, the expansion protruding portion 63 is too close to the electrode 7 of the mounting table 5, so that it is difficult to function as a counter electrode, and further, it may be caused by the heat of the mounting table 5. The expansion protrusion 63 is subjected to thermal damage.

Further, similarly, in order to prevent the expansion projecting portion 63 from being too close to the electrode 7 of the mounting table 5, the upper limit of the thickness of the expansion projecting portion 63 (that is, the distance between the upper face 63a and the lower face 63b) L2 is preferably, for example, 20 mm. . However, if the thickness L2 of the expanded projection 63 is too small, since the effect as the counter electrode is lowered, the lower limit of the thickness L2 is preferably, for example, 5 mm. Therefore, it is preferable that the thickness L2 of the expanded projection 63 is in the range of 5 mm or more and 20 mm or less, and more preferably in the range of 7 mm or more and 17 mm or less.

Further, in order to allow the expansion protruding portion 63 to function as a counter electrode, and as described above, in order to prevent the expansion protruding portion 63 from coming too close to the electrode 7 of the mounting table 5, it is preferable to extend the lower portion 63c of the expansion protruding portion 63 to the mounting table. The distance L3 in the upper aspect (herein, the difference in height position between the two components) is, for example, in the range of 15 mm or more and 60 mm or less, more preferably in the range of 20 mm or more and 25 mm or less.

Further, the plasma processing apparatus 103 of the present embodiment is configured such that the gas introduction port 15a is provided at the abutting support portion 60' at a position above the expanded protrusion 63 to supply the processing gas to the expansion protrusion 63 and the microwave. The space S1 between the plates 28 is penetrated. According to the above configuration, gas replacement and discharge in the space S1 directly under the microwave penetrating plate 28, which is a part of the plasma generating space S, can be promoted, and the processing gas can be more easily activated. As a result, plasma can be efficiently generated as a whole in the space S1 directly below the microwave penetrating plate 28. Further, regarding other effects, by supplying the processing gas to the space S1 directly under the microwave penetrating plate 28, when performing the plasma nitriding process, for example, in the plasma processing apparatus 103, it is possible to promote the production from quartz. The microwave passes through the discharge of oxygen released from the plate 28, so that the decrease in the nitrogen concentration in the nitride film formed is suppressed.

Further, the shape of the expansion protrusion 63 is not limited to the cross-sectional shape shown in FIG. 7, and may be, for example, an L-shaped cross section or an arbitrary shape in which a surface is provided with irregularities or grooves, and the shape may be increased in surface area. . However, from the viewpoint of preventing abnormal discharge or generation of particles at the surface of the expanded projection 63 facing the plasma generating space S, as shown in Fig. 7, it is preferable to shape the corner portion. Further, in the present embodiment, the protective film 48 is provided on the exposed surface of the contact supporting portion 60' and the expanded protruding portion 63 facing the plasma generating space S. The protective film 48 prevents metal contamination or particles from being splashed when the abutting support portion 60' and the expanded projection 63 are exposed to the plasma. Even if the protective film 48 is formed on the abutting support portion 60' and the expanded projection portion 63, the function as a counter electrode can be maintained to stably generate plasma and perform uniform plasma treatment. Further, when the entire expansion protrusion 63 is formed of ruthenium, a protective film may not be provided.

Other configurations and effects of this embodiment are the same as those of the first embodiment.

[Fifth Embodiment]

Next, a plasma processing apparatus according to a fifth embodiment of the present invention will be described with reference to Fig. 8. In addition, the plasma processing apparatus 104 of the fifth embodiment is the same as the first embodiment except for the features of the first embodiment. Therefore, the description of the entire configuration (the first drawing, the third drawing, and the fourth drawing) is omitted, and the eighth embodiment is omitted. In the drawings, the same components as those in FIG. 2A are denoted by the same reference numerals, and description thereof will be omitted.

In the plasma processing apparatus 103 of the fourth embodiment, the expansion protruding portion 63 (auxiliary electrode assembly) is attached to the lid assembly 27. However, the plasma processing apparatus 104 of the present embodiment is an expansion protruding portion 64 (annular auxiliary electrode assembly). It is detachably attached to the upper portion of the processing container 1. In this way, part or all of the counter electrode can also be formed by additionally providing components. By making the expansion projection 64 different from the assembly of the lid assembly 27 or the processing container 1, it can be easily replaced as a consumable. The expansion projection 64 has an upper surface 64a, a front end surface 64b, and a lower surface 64c. The upper portion 64a of the expansion projection 64 is provided with a step difference in conformity with the shape of the abutment support portion 60' of the lid assembly 27. Further, the lower portion 64c of the expansion projection 64 has a plurality of (two lanes in Fig. 8) annular grooves 64d.

The expansion protruding portion 64 is not particularly limited as long as it is a conductor. For example, in addition to a metal material such as aluminum or an alloy thereof or stainless steel, for example, tantalum or the like can be used. In the case where the expansion protrusions 64 are formed by ruthenium, it is advantageous because the surface does not need to be provided with a protective film. The expansion projection 64 can be fixed to the inner surface of the side wall 1b of the processing container 1 by any fixing direction such as a screw (not shown).

In the plasma processing apparatus 104 of the present embodiment, the expansion protruding portion 64 is formed to face the plasma generation space S, and is paired with the first electrode (the electrode 7 of the mounting table 5) with the plasma generation space S interposed therebetween. The main part of the counter electrode (second electrode) function. Specifically, from the abutting portion end portion of the abutting support portion 60' of the cap assembly 27 and the microwave penetrating plate 28 (the portion A shown in the circle in the figure), the abutting abutment supporting portion 60' is The exposed surface and the surface of the expansion protrusion 64 (that is, the upper portion 64a of the expansion protrusion 64, the front end surface 64b and the lower surface 64c) until the end portion of the expansion protrusion 64 is exposed (the circle in the figure) The inner peripheral surface of the display portion B) has a portion that functions as a counter electrode. In the present embodiment, the surfaces of the portions A to B are exposed to the plasma generation space S to form an annular counter electrode. Thereby, the counter electrode can be formed by a plurality of components (the cap assembly 27 and the expansion protrusion 64) having the surface facing the plasma generating space S. Then, by causing the annular member mainly forming the counter electrode to protrude toward the plasma generating space S, it is difficult to provide the counter electrode at a position directly above the mounting table 5 even if the microwave penetrating plate 28 is provided. In the RLSA mode microwave plasma processing apparatus 104, sufficient counter electrode surface area can still be ensured.

In the present embodiment, by additionally providing the expansion protruding portion 64 by the abutment supporting portion 60' of the cap assembly 27, the surface area of the portion having the function of the counter electrode can be sufficiently ensured. In this manner, by constituting the counter electrode by a combination of a plurality of components, the area of the counter electrode can be sufficiently ensured in the limited space in the processing container 1. In the present embodiment, the surface potential of the counter electrode exposed to the plasma generating space S can also suppress the vibration of the plasma potential, thereby generating a stable plasma in the processing container 1, and weakening the plasma near the counter electrode. The sputtering effect is preferably such that the area ratio of the electrode area for the bias voltage is 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and more preferably 2 or more and 4 or less. Within the scope.

Further, it is preferable that the protruding length of the tip end portion (front end surface 64b) of the expanding projection portion 64 having the counter electrode function does not reach the position P _WE of the peripheral end of the wafer W placed on the mounting table 5. If the front end of the expansion protrusion 64 is closer to the inner side than the position P _{WE of the} peripheral end of the wafer W, the high-density plasma area generated in the processing container 1 will be smaller than the wafer size, so that the wafer W The plasma density at the peripheral portion is reduced, and the processing content uniformity of the outer peripheral portion of the wafer W is adversely affected. On the other hand, at the opposite side of the front end portion (front end surface 64b) of the expansion protruding portion 64, the abutting end with the side wall 1b becomes the base end portion of the expansion protruding portion 64. However, in the present embodiment, it is on the way. The portion B is exposed to the plasma generation space S. In other words, in the present embodiment, the end portion of the portion 64c which is exposed to the expanded projection portion 64 of the counter electrode function is a contact point with the upper bushing 49a (shown as a portion B in Fig. 8).

Further, the upper portion 64a of the expansion projection 64 is disposed apart from the lower side of the microwave penetration plate 28. That is, the expansion protrusion 64 protrudes toward the plasma generation space S and is spaced apart from the microwave penetration plate 28 by the space L1. In this manner, by spacing the microwave penetration plate 28 and the expansion projection 64 at intervals L1, the effective area for microwave introduction of the microwave transmission plate 28 is not reduced, and the counter electrode can be sufficiently ensured. Surface area. Further, the space S1 is a part of the plasma generation space S, and plasma is generated also in the space S1, so that the plasma treatment of the wafer W can be made uniform. In contrast, the interval L1 is not provided, but the microwave penetration plate 28 and the expansion protrusion 64 are closely arranged. If the surface area of the counter electrode in the processing container 1 is to be increased, the microwave penetration plate must be increased. 28 The amount of protrusion on the center side. In this way, when the plasma is generated, since the effective area of the microwave penetrating plate 28 is reduced corresponding to the contact area with respect to the upper face 64b of the expanding protrusion 64, the supply of the microwave electric power in the processing container 1 is caused. The amount of electricity will be reduced to produce plasma, or it will become unstable even if it is produced. In order to solve this problem, it is necessary to increase the processing container 1, but if the installation area is increased, the manufacturing cost of the device will also increase.

Preferably, the interval L1 is greater than the thickness of the sheath between the plasma generated immediately below the microwave penetrating plate 28 and the microwave penetrating plate 28. Preferably, the interval L1 is in the range of, for example, 10 mm or more and 30 mm or less. It is preferably in the range of 20mm or more and 25mm or less. When the interval L1 is less than 10 mm, the plasma in the space S1 may be unstable due to abnormal discharge, and particularly when the interval L1 is equal to or less than the thickness of the sheath, the plasma in the processing container 1 may become difficult. . On the other hand, when the interval L1 exceeds 30 mm, the expansion protruding portion 64 is too close to the electrode 7 of the mounting table 5, so that it is difficult to function as a counter electrode, and the heat of the mounting table 5 may be caused by the heat of the mounting table 5. The expansion tab 64 is caused to suffer thermal damage.

Further, similarly, in order to prevent the expansion projecting portion 64 from being too close to the electrode 7 of the mounting table 5, the upper limit of the thickness of the expansion projecting portion 64 (that is, the distance between the upper face 64a and the lower face 64b) L2 is preferably, for example, 20 mm. . However, if the thickness L2 of the expansion protruding portion 64 is too small, since the effect as the counter electrode is lowered, the lower limit of the thickness L2 is preferably, for example, 5 mm. Therefore, it is preferable that the thickness L2 of the expansion protruding portion 64 is in the range of 5 mm or more and 20 mm or less, and more preferably in the range of 7 mm or more and 17 mm or less. Further, the depth of the groove 64d can be arbitrarily set.

Further, in order to allow the expansion protruding portion 64 to function as a counter electrode, and as described above, in order to prevent the expansion protruding portion 64 from approaching the electrode 7 of the mounting table 5, it is preferable to lower the end portion of the lower portion 64c of the expansion protruding portion 64. The distance L3 (herein, the difference in height position between the two components) on the mounting table 5 is, for example, in the range of 15 mm or more and 60 mm or less, and more preferably in the range of 20 mm or more and 25 mm or less.

Further, the plasma processing apparatus 104 of the present embodiment is configured such that the gas introduction port 15a is provided at the abutting support portion 60' at a position above the expanded protrusion 64 to supply the processing gas to the expansion protrusion 64 and the microwave. The space S1 between the plates 28 is penetrated. According to the above configuration, gas replacement and discharge in the space S1 directly under the microwave penetrating plate 28, which is a part of the plasma generating space S, can be promoted, and the processing gas can be more easily activated. As a result, plasma can be efficiently generated as a whole in the space S1 directly below the microwave penetrating plate 28. Further, regarding the secondary effect, by supplying the processing gas to the space S1 directly under the microwave penetrating plate 28, when performing the plasma nitriding process, for example, in the plasma processing apparatus 104, since it can be promoted from the quartz The discharge of oxygen released by the microwave penetration plate 28 is suppressed, so that the decrease in the nitrogen concentration in the nitride film formed is suppressed.

The expanded protruding portion 64 of Fig. 8 is provided with two annular grooves 64d in the lower surface 64c in order to secure the surface area. However, the shape of the expanded portion 64d is not limited to the cross-sectional shape shown in Fig. 8 as long as it can increase the surface area. The shape of the expansion protruding portion 64 may be any shape such as a ring shape or a shape in which a plurality of holes are formed in an arbitrary arrangement. However, from the viewpoint of preventing abnormal discharge or generation of particles at the surface of the expanded projection 64 facing the plasma generating space S, as shown in Fig. 8, it is preferable to shape the corners. Further, in Fig. 8, the expansion projection 64 abuts against the abutment support portion 60' of the cap assembly 27, but may be separated from the abutment support portion 60'.

Further, in the present embodiment, the protective film 48 is provided on the exposed surface of the contact supporting portion 60' facing the plasma generating space S. On the other hand, when the entire expansion protruding portion 64 is formed of ruthenium, a protective film may not be provided. However, when the expansion protrusion 64 is formed of a metal material such as aluminum, for example, it may be sprayed with a plasma onto the surface of the SiO ₂ film or the like to provide a protective film. Further, even if the protective film 48 is formed, the function as a counter electrode can be maintained to stably generate plasma and perform uniform plasma treatment.

Other configurations and effects of this embodiment are the same as those of the first embodiment.

The feature structures described in the first to fifth embodiments described above can be combined with each other. For example, the expanded protrusion 60B of the first embodiment (Fig. 1, Fig. 2A, and Fig. 2B) or the expanded protrusion 62 of the third embodiment (Fig. 6) can be used as the second embodiment. Concavities and convexities are generally provided to further increase the surface area. Similarly, in the fourth embodiment (Fig. 7) and the fifth embodiment (Fig. 8), the projecting portions 63 and 64 can be provided with irregularities as in the second embodiment to further increase the surface area.

Moreover, the cover assembly 27 and the processing container 1 may be provided with a protruding portion having a function of the opposite electrode, or the cover assembly 27 and the processing container 1 may be provided with an auxiliary electrode assembly having an opposite electrode function (the expansion protruding portion 63, 64).

Next, the functional effects of the present invention will be described based on experimental results. In the plasma processing apparatus having the same configuration as that of the plasma processing apparatus 100 of Fig. 1, when a high-frequency voltage is applied to the electrode 7 of the mounting table 5, and the potential of the mounting table 5 is measured, the 9A and 9B are generated. The figure shows the AC waveform. Fig. 9A shows a case where the surface area of the counter electrode is insufficient with respect to the area of the bias electrode, and Fig. 9B shows a case where the surface area of the counter electrode is sufficient with respect to the area of the electrode for bias. In the figure, Vmax is the maximum value of the high-frequency voltage amplitude of the stage 5, and generally, the potential difference of Vmax-GND (ground potential) has a relationship with the amplitude of the vibration of the plasma potential (Vp). In the 9A diagram in which the surface area of the counter electrode is not sufficient with respect to the area of the electrode for biasing, Vp vibrates due to high frequency, and Vmax becomes large. On the other hand, in the 9B chart in which the surface area of the counter electrode is sufficient with respect to the area of the electrode for biasing, the plasma potential hardly changes, and a self-bias voltage (Vdc) can be generated.

Next, Fig. 10 shows the results of investigation of the relationship between the amount of aluminum (Al) contamination generated by plasma oxidation treatment and Vmax when the plasma treatment treatment is changed in the plasma processing apparatus. The processing conditions are as follows. The treatment pressure is 6.67 Pa, 20 Pa or 40 Pa. The treatment gas system uses Ar gas and O ₂ gas, and the oxygen flow rate ratio in the treatment gas is 0.5% by volume, 1% by volume, 25% by volume, or 50% by volume. Further, the bias high frequency electric power frequency supplied to the electrode 7 of the mounting table 5 is 13.56 MHz, and the high frequency electric power is 450 W, 600 W or 900 W. As can be seen from Fig. 10, regardless of the processing conditions, when Vmax rises, Al contamination increases proportionally. The cause of the Al contamination is believed to be due to sputtering by the Al cap assembly 27. In order to suppress Al contamination, it is effective to suppress Vmax to a lower value, and it has been known that the Al contamination is suppressed to, for example, 7 × 10 ¹⁰ (atoms/cm ² ) or less, as long as Vmax is 70 V or less. Then, in order to suppress Vmax, as shown in Fig. 9B, it is effective to make the surface area of the counter electrode larger than the area of the electrode for biasing.

At this time, an experiment was conducted in order to investigate the change in Vmax when the surface area of the counter electrode was changed while fixing the electrode area for the bias voltage. 11 to 16 show the area ratio (horizontal axis) of the counter electrode when the plasma oxidation treatment is performed under various treatment conditions in the plasma processing apparatus having the same configuration as that of the plasma processing apparatus 100 of Fig. 1. A graph of the relationship of Vmax (vertical axis). Here, the counter electrode area ratio refers to a value obtained by dividing the surface area of the counter electrode by the area of the electrode for bias. In addition, the process gas system uses Ar gas and oxygen. Further, the bias high frequency electric power frequency supplied to the electrode 7 of the mounting table 5 is 13.56 MHz, and the high frequency electric power is 0 W (not applied), 300 W, 450 W, 600 W or 900 W.

Fig. 11 shows the experimental results when the treatment pressure was 6.67 Pa, the oxygen flow rate ratio was 0.5% by volume, and the microwave electric power for generating plasma was set at 1200 W. Fig. 12 shows the experimental results when the treatment pressure was 6.67 Pa, the oxygen flow rate was 50% by volume, and the microwave electric power was set at 3400 W. Fig. 13 shows the experimental results when the treatment pressure was 20 Pa, the oxygen flow rate was 0.5% by volume, and the microwave electric power was set at 1200 W. Fig. 14 shows the experimental results when the treatment pressure was 20 Pa, the oxygen flow rate was 50% by volume, and the microwave electric power was set at 3400 W. Fig. 15 shows the experimental results when the treatment pressure was 40 Pa, the oxygen flow rate was 0.5% by volume, and the microwave electric power was set at 1200 W. Fig. 16 shows the experimental results when the treatment pressure was 40 Pa, the oxygen flow rate was 50% by volume, and the microwave electric power was set at 3400 W. The electrode surface area of ^{500cm 2, 1400cm 2, 1800cm 2} , 2200cm 2 or 3150cm ^2, bias electrode area of 855cm ^2.

As can be seen from the graphs of Figures 11 to 16, as the ratio of the opposing electrode areas increases, Vmax decreases. Further, this tendency is most remarkable when the treatment pressure is 6.67 Pa, and it is confirmed that the lower the pressure, the better the suppression effect of Vmax obtained by increasing the area ratio of the counter electrode. In the plasma processing apparatus having the same configuration as that of the plasma processing apparatus 100 of Fig. 1, in order to obtain the effect of suppressing Vmax by increasing the ratio of the opposing electrode area, it is preferable to carry out the electricity at a processing pressure of 40 Pa or less. Slurry treatment.

Based on the above results, in the plasma processing apparatus having the same configuration as that of the plasma processing apparatus 100 of Fig. 1, the amount of aluminum (Al) contamination generated when the plasma oxidation treatment was performed to change the surface area of the counter electrode was investigated. In this experiment, the surface area of the counter electrode was 2200 cm ² (area ratio: large), 1800 cm ² (area ratio: medium), or 500 cm ² (area ratio: small), and the electrode area for biasing was 855 cm ² . Further, the treatment pressure was set to a different pressure condition in the range of 6.67 Pa to 40 Pa. The result is shown in Fig. 17. In addition, the marks "5.0E10" and "1.8E11" in Fig. 17 indicate that the amount of Al contamination is "5.0 × 10 ¹⁰ ", "1.8 × 10 ¹¹ ", and the like. From this result, when the surface area of the counter electrode is 2200 cm ² (area ratio: large) or 1800 cm ² (area ratio: medium), Vmax can be suppressed to 70 V or less at a treatment pressure of 40 Pa or less (refer to Fig. 10). ), and Al contamination is also a value that is sufficiently suppressed. However, when the surface area of the counter electrode is 500 cm ² (area ratio: small), Vmax cannot be suppressed to 70 V or less at a treatment pressure of 20 Pa or less (refer to Fig. 10), and Al contamination is also greatly increased. From this result, it is understood that the Vmax is suppressed to 70 V or less, and the surface area of the counter electrode is set to 1800 cm ² (area ratio: medium) or more. Therefore, the counter electrode area ratio (opposing electrode surface area/biasing electrode area) is preferably 1 or more and 5 or less, more preferably 2 or more and 5 or less, and desirably 2 or more and 4 or less.

Next, in the plasma processing apparatus having the same configuration as that of the plasma processing apparatus 100 of Fig. 1, a verification experiment was performed on the effect of the difference in the introduction position of the processing gas. In this experiment, in the plasma nitriding treatment, the case where the processing gas is introduced from the gas introduction port 15a of Fig. 1 (the embodiment; the first pattern) and the side wall 1b below the protruding portion 60 are provided. The amount of oxygen in the tantalum nitride film in the case where the processing gas is introduced into the annular gas ring (comparative example; omitted in the drawing). The plasma nitriding treatment is performed on the surface of the wafer W having a diameter of 300 mm. The amount of oxygen in the tantalum nitride film is measured by the X-ray photoelectron analyzer (XPS) for the central portion and the edge portion of the wafer W.

The conditions of the plasma nitriding treatment are as follows, changing the N ₂ flow ratio, the processing pressure, and the high frequency bias electric power.

<N ₂ flow ratio 17%>

N ₂ flow rate: 333 mL/min (sccm), Ar flow rate: 1667 mL/min (sccm)

<N ₂ flow ratio 40%>

N ₂ flow rate: 800 mL/min (sccm), Ar flow rate: 1200 mL/min (sccm)

Processing pressure: 6.67Pa, 20Pa or 133Pa

Microwave electric power: 1500W

High frequency bias power: 0W (not applied), 450W or 900W

Processing time: 90 seconds

Fig. 18A shows the oxygen amount measurement result in the tantalum nitride film at the central portion of the wafer W, and Fig. 18B shows the oxygen amount measurement result in the tantalum nitride film at the edge portion of the wafer W. In the comparative example in which the processing gas was introduced from the gas introduction port 15a in the comparative example in which the processing gas was introduced from the position below the protruding portion 60, it was confirmed that the niobium nitride film was in the range of the processing pressure of 6.67 Pa to 133 Pa. The oxygen concentration in the solution will decrease. The decrease in the oxygen concentration in the examples is considered to be irrespective of whether or not a high-frequency bias is applied, and the same tendency is exhibited in the central portion or the edge portion of the wafer W. In the measurement results of the edge portion of the wafer W having a high oxygen concentration and a treatment pressure of 133 Pa, it was confirmed that the oxygen concentration was reduced by about 8% in the embodiment as compared with the comparative example.

In order to increase the area of the counter electrode, in the plasma processing apparatus having the same structure as that of the first embodiment in which the expansion protrusion 60B is provided, the closed space S1 between the expansion protrusion 60B and the microwave penetration plate 28 may have gas retention. When the plasma nitriding treatment is performed, it is likely to cause oxygen to be mixed into the tantalum nitride film. The oxygen intrusion is caused when the oxygen present in the microwave penetrating plate 28 is released into the plasma generating space S by the action of the plasma, and is mixed into the tantalum nitride film formed by the plasma nitriding treatment. In the comparative example, since the processing gas is introduced from the position below the protruding portion 60, gas retention occurs in the space S1 directly below the microwave penetrating plate 28. As a result, the oxygen released from the microwave penetrating plate 28 may remain in the space S1 for a long time, and it is difficult to discharge from the inside of the processing container 1, resulting in an increase in the probability of oxygen being mixed into the tantalum nitride film on the surface of the wafer W. On the other hand, in the embodiment, by introducing the processing gas from the gas introduction port 15a into the space S1 directly below the microwave penetrating plate 28, the oxygen discharged from the microwave penetrating plate 28 can be quickly moved from the space S1. Go out. As a result, since oxygen can be efficiently discharged to the outside of the processing container 1, it is believed that oxygen can be mixed into the tantalum nitride film on the wafer W.

As described in detail above, in the plasma processing apparatus according to each of the embodiments of the present invention, the processing chamber 1 or the cap assembly 27 faces the plasma generating space S and is spaced apart from the microwave penetrating plate 28 by the space L1. The protruding protrusions 60B, 61B, 62, 63, and 64 are formed so as to protrude from at least a part of the counter electrode that is paired with the electrode 7 via the plasma generating space S, so that the area of the counter electrode can be sufficiently ensured. And suppress the vibration of the plasma potential (Vp). Further, by increasing the area of the counter electrode, it is possible to suppress the phenomenon that the surface of the counter electrode is sputtered by the action of the plasma, thereby preventing contamination. Further, by sufficiently ensuring the area of the counter electrode, it is possible to suppress short-circuiting or abnormal discharge in other portions. Furthermore, since the expansion protrusions 60B, 61B, 62, 63, 64 are provided at intervals from the microwave penetration plate 28, the effective area of the microwave penetration plate 28 is not reduced, and sufficient introduction is possible. The microwave electric power forms a stable plasma in the processing container 1.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above. For example, in the above embodiment, the cover assembly 27 supporting the microwave penetration plate 28 is a configuration example of a portion of the microwave introduction portion 26, but the cover assembly 27 supporting the microwave penetration plate 28 may also be the processing container 1. Part of it.

Further, in the above embodiment, the gas introduction port 15a is provided in the lid unit 27, but the gas introduction port 15a may be provided in a unit other than the lid unit 27. For example, Fig. 19 shows a plasma processing apparatus 102A which is a modification of the embodiment in which the expansion protrusion 62 is integrally formed with the side wall 1b of the processing container 1 (third embodiment; see Fig. 6). The main part is a sectional view. As shown in Fig. 19, by forming the groove-shaped annular passage 13A provided at the upper end of the side wall 1b of the processing container 1, and forming the gas introduction path 15b communicating with the annular passage 13A in the side wall 1b, The gas introduction port 15a is provided in the upper portion of the side wall 1b. Even in this case, the processing gas can be supplied from the gas introduction port 15a to the space S1 between the microwave penetrating plate 28 and the expansion protruding portion 62.

Further, in the above embodiment, the experimental results in the case where aluminum is used as the body material of the cap assembly 27 exposed to the plasma assembly have been shown, but the same effect can be obtained when other metals such as stainless steel are used.

Further, the enlarged protruding portion is not limited to the annular shape, and may be a shape in which a plurality of enlarged protruding portions that are separated from each other protrude toward the plasma generating space S.

Further, the content of the plasma treatment is not limited to the plasma oxidation treatment or the plasma nitridation treatment as long as it is a process of supplying the high-frequency electric power to the electrode 7 of the mounting table 5, for example, plasma CVD treatment or etching. Various plasma treatments such as treatment can also be applied. In addition, the object to be processed is not limited to the semiconductor wafer, and other substrates such as a glass substrate for FPD may be applied.

1. . . Processing container

1a. . . Bottom wall

1b. . . Side wall

3a. . . Cooling water channel

4. . . Support

5. . . Mounting table

5a. . . Heater

6. . . Heater power supply

6a. . . Power supply line

7. . . electrode

8a. . . Cover

8b. . . Blocker

8c. . . Multiple holes

9a. . . Sealing assembly

9b. . . Sealing assembly

10. . . Opening

11. . . Exhaust chamber

11a. . . space

11b. . . exhaust vent

12. . . Gas supply channel

12a. . . Gas supply pipe

13. . . Annular channel

15a. . . Gas inlet

15b. . . Gas introduction path

16. . . Gas supply device

18. . . Step difference

19. . . Step difference

twenty three. . . exhaust pipe

twenty four. . . Exhaust

26. . . Microwave introduction

27. . . Cover assembly

27a. . . Refrigerant channel

28. . . Microwave penetrating plate

29. . . Sealing assembly

31. . . Planar antenna

32. . . Slot

33. . . Slow wave material

34. . . Cover

34a. . . Refrigerant channel

34b. . . Opening

35. . . Ring buckle

36. . . Fixed component

37. . . Waveguide

37a. . . Coaxial waveguide

37b. . . Rectangular waveguide

38. . . Matching circuit

39. . . Microwave generating device

40. . . Mode converter

41. . . Inner conductor

42. . . Power supply line

43. . . Matcher

44. . . High frequency power supply

45. . . Filter box

46. . . Shield box

47. . . Conductive plate

48. . . Protective film

49a. . . Upper bushing

49b. . . Lower bushing

50. . . Control department

51. . . Process controller

52. . . user interface

53. . . Memory department

60. . . Protruding

60A. . . Abutment support

60’. . . Abutment support

60B. . . Expansion protrusion

60B1. . . Upper aspect

60B2. . . Front end face

60B3. . . The next aspect

61B. . . Expansion protrusion

62. . . Expansion protrusion

63. . . Expansion protrusion

64. . . Expansion protrusion

64a. . . Upper aspect

64b. . . Front end face

64c. . . The next aspect

64d. . . ditch

100. . . Plasma processing device

101. . . Plasma processing device

102. . . Plasma processing device

102A. . . Plasma processing device

103. . . Plasma processing device

A. . . Part

B. . . Part

G. . . gap

Pwe. . . position

L1. . . interval

L2. . . thickness

L3. . . distance

S. . . Plasma generation space

S1. . . space

W. . . Wafer (processed object)

Fig. 1 is a schematic cross-sectional view showing a plasma processing apparatus according to a first embodiment of the present invention.

Fig. 2A is an enlarged cross-sectional view showing the essential part of Fig. 1.

Figure 2B is a perspective view showing the appearance of the lid assembly.

Figure 3A is a diagram showing the construction of a planar antenna.

Figure 3B is a graph showing the results of measuring the electron density and electron temperature in the processing vessel for different processing pressures and gaps.

Fig. 4 is an explanatory view showing the structure of the control unit.

Fig. 5 is a cross-sectional view showing an essential part of a plasma processing apparatus according to a second embodiment of the present invention.

Fig. 6 is a cross-sectional view showing an essential part of a plasma processing apparatus according to a third embodiment of the present invention.

Fig. 7 is a cross-sectional view showing an essential part of a plasma processing apparatus according to a fourth embodiment of the present invention.

Fig. 8 is a cross-sectional view showing an essential part of a plasma processing apparatus according to a fifth embodiment of the present invention.

Fig. 9A is an explanatory view showing the potential of the mounting stage when a high-frequency voltage is applied to the electrodes of the mounting table when the area of the electrode for biasing is insufficient with respect to the surface area of the counter electrode.

Fig. 9B is an explanatory view showing the potential of the mounting stage when a high-frequency voltage is applied to the electrodes of the mounting table when the area of the electrode for biasing is sufficient with respect to the surface area of the counter electrode.

Fig. 10 is a graph showing the relationship between the amount of aluminum (Al) contamination and Vmax in the plasma oxidation treatment.

Fig. 11 is a graph showing the relationship between the opposing electrode area ratio (horizontal axis) and Vmax (vertical axis) in the plasma oxidation treatment.

Fig. 12 is a graph showing the relationship between the area ratio of the counter electrode (horizontal axis) and Vmax (vertical axis) in the plasma oxidation treatment under other conditions.

Fig. 13 is a graph showing the relationship between the opposing electrode area ratio (horizontal axis) and Vmax (vertical axis) in the plasma oxidation treatment under still other conditions.

Fig. 14 is a graph showing the relationship between the area ratio of the counter electrode (horizontal axis) and Vmax (vertical axis) in the plasma oxidation treatment under still other conditions.

Fig. 15 is a graph showing the relationship between the area ratio (horizontal axis) of the counter electrode and Vmax (vertical axis) in the plasma oxidation treatment under still other conditions.

Fig. 16 is a graph showing the relationship between the opposing electrode area ratio (horizontal axis) and Vmax (vertical axis) in the plasma oxidation treatment under still other conditions.

Fig. 17 is a graph showing the Vmax (vertical axis) and aluminum (Al) contamination amount in the plasma oxidation treatment performed by changing the treatment pressure and the counter electrode area ratio.

Fig. 18A is a graph showing the measurement results of the oxygen amount at the central portion of the wafer in the plasma nitriding treatment.

Fig. 18B is a graph showing the measurement results of the oxygen amount at the edge portion of the wafer in the plasma nitriding process.

Fig. 19 is a cross-sectional view showing an essential part of a modification of the plasma processing apparatus according to the third embodiment of the present invention.

1. . . Processing container

1a. . . Bottom wall

1b. . . Side wall

3a. . . Cooling water channel

4. . . Support

5. . . Mounting table

5a. . . Heater

6. . . Heater power supply

6a. . . Power supply line

7. . . electrode

8a. . . Cover

8b. . . Blocker

8c. . . Multiple holes

9a. . . Sealing assembly

9b. . . Sealing assembly

10. . . Open mouth

11. . . Exhaust chamber

11a. . . space

11b. . . exhaust vent

12. . . Gas supply channel

12a. . . Gas supply pipe

16. . . Gas supply device

twenty three. . . exhaust pipe

twenty four. . . Exhaust

26. . . Microwave introduction

27. . . Cover assembly

27a. . . Refrigerant channel

28. . . Microwave penetrating plate

29. . . Sealing assembly

31. . . Planar antenna

32. . . Slot

33. . . Slow wave material

34. . . Cover

34a. . . Refrigerant channel

34b. . . Opening

35. . . Ring buckle

36. . . Fixed component

37. . . Waveguide

37a. . . Coaxial waveguide

37b. . . Rectangular waveguide

38. . . Matching circuit

39. . . Microwave generating device

40. . . Mode converter

41. . . Inner conductor

42. . . Power supply line

43. . . Matcher

44. . . High frequency power supply

45. . . Filter box

46. . . Shield box

47. . . Conductive plate

49a. . . Upper bushing

49b. . . Lower bushing

50. . . Control department

60. . . Protruding

100. . . Plasma processing device

Pwe. . . position

G. . . gap

S. . . Plasma generation space

W. . . Wafer (processed object)

Claims (16)

A plasma processing apparatus comprising: a processing container, wherein an opening is formed in an upper portion, and the object to be processed is processed using plasma; and a mounting table is placed in the processing container to mount the object to be processed; and the first electrode Is embedded in the mounting table and applies a bias voltage to the object to be processed; the dielectric plate closes the opening of the processing container to define a plasma generating space, and allows microwave penetration to be introduced into the processing container a planar antenna disposed above the dielectric plate and introducing microwaves generated by the microwave generating device into the processing container via the dielectric plate; the cover assembly is disposed on the upper portion of the processing container And having an abutting support portion protruding toward the plasma generating space on the inner peripheral side thereof to support the outer peripheral portion of the dielectric body plate by the abutting support portion; the annular expansion protruding portion Forming a space from the processing container or the abutting support portion toward the plasma in the processing container, and protruding from the dielectric plate at a distance from each other, and forming a space between the plasma and the first 1 electrode in pairs At least a portion of the second electrode; and a space is formed between the line and below the dielectric plate aspects for the expansion portion protrudes above. The plasma processing apparatus according to claim 1, wherein an interval between the upper side of the expanded protrusion and the lower side of the dielectric board is in a range of 10 mm or more and 30 mm or less. The plasma processing apparatus according to claim 1 or 2, wherein the expansion projection is provided such that the protruding amount of the front end does not reach above the end of the object to be processed placed on the mounting table. The plasma processing apparatus according to claim 1 or 2, wherein a space between the dielectric body plate and the expansion protrusion is provided with a gas introduction port into which a processing gas is introduced. A plasma processing apparatus according to claim 1 or 2, wherein the expansion projection is integrally formed with the cap assembly. A plasma processing apparatus according to claim 1 or 2, wherein the expansion protrusion is integrally formed with the processing container. A plasma processing apparatus according to claim 1 or 2, wherein the expansion protrusion is fixed to an auxiliary electrode assembly of the cap assembly. A plasma processing apparatus according to claim 1 or 2, wherein the expansion protrusion is fixed to an auxiliary electrode assembly of the processing container. A plasma processing apparatus according to claim 1 or 2, wherein the surface of the expansion protrusion is provided with irregularities. The plasma processing apparatus according to claim 1 or 2, wherein a surface area of the second electrode facing the plasma generating space is compared with an area of the buried region of the first electrode of the mounting table. It is in the range of 1 or more and 5 or less. The plasma processing apparatus according to claim 1 or 2, wherein the surface of the expansion protrusion is further provided with a protective film. The plasma processing apparatus of claim 11, wherein the protective film is made of tantalum. The plasma processing apparatus according to claim 1 or 2, further comprising an insulating plate along the inner wall of the processing container at a position lower than a mounting surface of the mounting table. The plasma processing apparatus of claim 13, wherein the insulating sheet is formed to reach a position of the exhaust chamber continuously disposed at a lower portion of the processing container. A plasma processing method uses a plasma processing apparatus to generate a plasma in a processing container and process the object to be processed by the plasma; wherein the plasma processing apparatus is provided with a processing container attached to the upper portion An opening is formed, and the object to be processed is treated with plasma; the mounting table is placed in the processing container, and the object to be processed is placed; the first electrode is embedded in the mounting table, and a bias voltage is applied to be processed. a dielectric plate that closes an opening of the processing container to define a plasma generating space, and allows microwaves to be introduced into the processing container; a planar antenna is disposed above the dielectric plate, and will The microwave generated by the microwave generating device is introduced into the processing container through the dielectric plate; the cap assembly is disposed on the upper portion of the processing container to have an annular shape, and has a space protruding toward the plasma on the inner peripheral side thereof. Abutting the support portion to support the outer peripheral portion of the dielectric plate by the upper portion of the abutting support portion; the annular expansion protruding portion is directed from the processing container or the abutting support portion into the processing container The plasma generating space protrudes from the dielectric plate at intervals, and constitutes at least a part of the second electrode that is paired with the first electrode via the plasma generating space; and a space is formed Between the expansion protrusion and the underside of the dielectric plate. The plasma processing method of claim 15, wherein the processing pressure in the processing container is 40 Pa or less.